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SQL Partition By Explained
 
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Using Oracle's SQL, I'll explain how to use Partition By. This will be similar in other SQL engines that have the Partition By keyword.
Views: 35382 Pretty Printed
How to use partitioning to improve performance of large tables
 
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In this video we cover in much more detail the improvement in performance that can be achieved by using partitioning. MS SQL server databases can scale well using this feature. We cover how partitioning a table gives similar performance as a single table with a clustered index, we then explore how adding NC index improve performance of the heap table as well as the partitioned table.
Views: 20441 Jayanth Kurup
Oracle Partition By clause, Oracle Analytic Functions tutorial
 
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More about analytic functions, visit https://www.youtube.com/watch?v=Ukekis8C-SI&list=PL99-DcFspRUoscBHdh39T8EHENfm2VcQ3&index=2 Oracle Analytic Functions and Over By Partition clause enable calculating cumulative and moving aggregates returning multiple rows for each group.
Over clause in SQL Server
 
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over partition by in sql server 2008 sql server over clause partition partition by clause in sql server 2008 over partition by clause in sql In this video we will discuss the power and use of Over clause in SQL Server. The OVER clause combined with PARTITION BY is used to break up data into partitions. Syntax : function (...) OVER (PARTITION BY col1, Col2, ...) The specified function operates for each partition. For example : COUNT(Gender) OVER (PARTITION BY Gender) will partition the data by GENDER i.e there will 2 partitions (Male and Female) and then the COUNT() function is applied over each partition. Any of the following functions can be used. Please note this is not the complete list. COUNT(), AVG(), SUM(), MIN(), MAX(), ROW_NUMBER(), RANK(), DENSE_RANK() etc. Example : SQl Script to create Employees table Create Table Employees ( Id int primary key, Name nvarchar(50), Gender nvarchar(10), Salary int ) Go Insert Into Employees Values (1, 'Mark', 'Male', 5000) Insert Into Employees Values (2, 'John', 'Male', 4500) Insert Into Employees Values (3, 'Pam', 'Female', 5500) Insert Into Employees Values (4, 'Sara', 'Female', 4000) Insert Into Employees Values (5, 'Todd', 'Male', 3500) Insert Into Employees Values (6, 'Mary', 'Female', 5000) Insert Into Employees Values (7, 'Ben', 'Male', 6500) Insert Into Employees Values (8, 'Jodi', 'Female', 7000) Insert Into Employees Values (9, 'Tom', 'Male', 5500) Insert Into Employees Values (10, 'Ron', 'Male', 5000) Go Write a query to retrieve total count of employees by Gender. Also in the result we want Average, Minimum and Maximum salary by Gender. This can be very easily achieved using a simple GROUP BY query as show below. SELECT Gender, COUNT(*) AS GenderTotal, AVG(Salary) AS AvgSal, MIN(Salary) AS MinSal, MAX(Salary) AS MaxSal FROM Employees GROUP BY Gender What if we want non-aggregated values (like employee Name and Salary) in result set along with aggregated values You cannot include non-aggregated columns in the GROUP BY query. SELECT Name, Salary, Gender, COUNT(*) AS GenderTotal, AVG(Salary) AS AvgSal, MIN(Salary) AS MinSal, MAX(Salary) AS MaxSal FROM Employees GROUP BY Gender The above query will result in the following error : Column 'Employees.Name' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause One way to achieve this is by including the aggregations in a subquery and then JOINING it with the main query as shown in the example below. Look at the amount of T-SQL code we have to write. SELECT Name, Salary, Employees.Gender, Genders.GenderTotals, Genders.AvgSal, Genders.MinSal, Genders.MaxSal FROM Employees INNER JOIN (SELECT Gender, COUNT(*) AS GenderTotals, AVG(Salary) AS AvgSal, MIN(Salary) AS MinSal, MAX(Salary) AS MaxSal FROM Employees GROUP BY Gender) AS Genders ON Genders.Gender = Employees.Gender Better way of doing this is by using the OVER clause combined with PARTITION BY SELECT Name, Salary, Gender, COUNT(Gender) OVER(PARTITION BY Gender) AS GenderTotals, AVG(Salary) OVER(PARTITION BY Gender) AS AvgSal, MIN(Salary) OVER(PARTITION BY Gender) AS MinSal, MAX(Salary) OVER(PARTITION BY Gender) AS MaxSal FROM Employees Text version of the video http://csharp-video-tutorials.blogspot.com/2015/09/over-clause-in-sql-server.html Slides http://csharp-video-tutorials.blogspot.com/2015/09/over-clause-in-sql-server_29.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 95653 kudvenkat
SQL query to find first record and last record in single query
 
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SQL query to find first record and last record in single query
Views: 11457 SQL Guru
Query Analysis and Optimizing in Oracle
 
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Database Management Systems 11. Query Analysis and Optimizing in Oracle ADUni
Views: 85375 Chao Xu
SELECT statement Processing in an Oracle Database - DBArch  Video 7
 
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You will learn from this video how a SELECT statement is processed in an Oracle Database. You will learn about the a Parse, Execute and Fetch phases in a select statement. Our Upcoming Online Course Schedule is available in the url below https://docs.google.com/spreadsheets/d/1qKpKf32Zn_SSvbeDblv2UCjvtHIS1ad2_VXHh2m08yY/edit#gid=0 Reach us at [email protected]
Views: 36853 Ramkumar Swaminathan
Oracle Database 12c: Better PL/SQL From SQL
 
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Overview and demonstration of using the plsql_declarations clause to embed a PL/SQL function in a SQL SELECT statement. "plsql_declarations" in Oracle® Database SQL Language Reference http://www.oracle.com/pls/topic/lookup?ctx=db121&id=BABJCBCC
Views: 2857 OracleDBVision
01 Overview of table Partition in oracle
 
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Partitioning enhances the performance, manageability, and availability of a wide variety of applications and helps reduce the total cost of ownership for storing large amounts of data. Partitioning allows tables, indexes, and index-organized tables to be subdivided into smaller pieces, enabling these database objects to be managed and accessed at a finer level of granularity. Oracle provides a rich variety of partitioning strategies and extensions to address every business requirement. Moreover, since it is entirely transparent, partitioning can be applied to almost any application without the need for potentially expensive and time consuming application changes. Partitioning allows a table, index, or index-organized table to be subdivided into smaller pieces, where each piece of such a database object is called a partition. Each partition has its own name, and may optionally have its own storage characteristics. From the perspective of a database administrator, a partitioned object has multiple pieces that can be managed either collectively or individually. This gives the administrator considerable flexibility in managing partitioned objects. However, from the perspective of the application, a partitioned table is identical to a non-partitioned table; no modifications are necessary when accessing a partitioned table using SQL queries and DML statements. Partitioning Key ======================== Each row in a partitioned table is unambiguously assigned to a single partition. The partitioning key is comprised of one or more columns that determine the partition where each row will be stored. Oracle automatically directs insert, update, and delete operations to the appropriate partition through the use of the partitioning key. When to Partition a Table ========================== Here are some suggestions for when to partition a table: Tables greater than 2 GB should always be considered as candidates for partitioning. Tables containing historical data, in which new data is added into the newest partition. A typical example is a historical table where only the current month's data is updatable and the other 11 months are read only. When the contents of a table need to be distributed across different types of storage devices. When to Partition an Index ============================= Here are some suggestions for when to consider partitioning an index: Avoid rebuilding the entire index when data is removed. Perform maintenance on parts of the data without invalidating the entire index. Reduce the impact of index skew caused by an index on a column with a monotonically increasing value. Partitioned Index-Organized Tables =================================== Partitioned index-organized tables are very useful for providing improved performance, manageability, and availability for index-organized tables. For partitioning an index-organized table: ============================================ Partition columns must be a subset of the primary key columns Secondary indexes can be partitioned (both locally and globally) OVERFLOW data segments are always equi-partitioned with the table partitions See Also: Oracle Database Concepts for more information about index-organized tables System Partitioning System partitioning enables application-controlled partitioning without having the database controlling the data placement. The database simply provides the ability to break down a table into partitions without knowing what the individual partitions are going to be used for. All aspects of partitioning have to be controlled by the application. For example, an insertion into a system partitioned table without the explicit specification of a partition will fail. System partitioning provides the well-known benefits of partitioning (scalability, availability, and manageability), but the partitioning and actual data placement are controlled by the application. See Also: Oracle Database Data Cartridge Developer's Guide for more information about system partitioning Partitioning for Information Lifecycle Management Information Lifecycle Management (ILM) is concerned with managing data during its lifetime. Partitioning plays a key role in ILM because it enables groups of data (that is, partitions) to be distributed across different types of storage devices and managed individually.
Views: 7502 Md Arshad
Advanced SQL Queries in Oracle and SQL Server - What is PARTITION BY?
 
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This video clip, on the PARTITION BY Clause used with analytic functions, is taken from my www.pluralsight.com course "Advanced SQL Queries in Oracle and SQL Server". Click here to learn more about this course: http://www.pluralsight.com/courses/adv-sql-queries-oracle-sql-server?utm_source=youtube&utm_medium=video&utm_campaign=authordemo.
Views: 5503 sheepsqueezersYT
How to Fetch Latest record/row from the Table in Oracle Database
 
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You will learn how to How to Fetch Latest record/row from the Table in Oracle Database. Realtime Scenario: This logic can be implemented to find whether the latest record should be inserted or updated to datawarehouse
T-SQL: Over() and Partition By
 
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Show how to use OVER and PARTITION BY to get groups of data with aggregation.
Views: 10211 MidnightDBA
Oracle sql Interview Question : How to change rows to column
 
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This video tutorial talks about the frequently asked oracle sql interview question of changing rows to the column. Based on the given scenario, we are asked to change the presentation of data in a table with 3 rows and 2 column to 3 columns and 2 rows. Decode Function in oracle https://youtu.be/YUAjPMjqMws Pivot and unpivot in oracle https://youtu.be/6s0DI1YcWIM
Views: 19340 Kishan Mashru
Oracle SQL Tutorial 9 - Intro to Queries
 
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This video is for beginners who have never worked with SQL Developer, and we are going to teach how to begin writing queries. So the queries we are going to start with are queries when we give the database an expression and it will return back some kind of value. The most common keyword you are going to need to know for Oracle is SELECT. SELECT is the command we use to get data from the database. Even though we have not really put any data in our database, we can still use the SELECT statement to get data. That's because the database is capable of doing more than just creating tables and retrieving data from tables. So our first goal is to essentially write a Hello World, which just displays the text hello world to us. A good place to start is with: SELECT 'Hello World' This would actually work for many database management systems, but when you run it you will get an error. This actually doesn't work with Oracle, it will tell us we always need the FROM keyword. To get around this, there is a magical table called DUAL. We can put anything we want to SELECT and then say FROM DUAL and it will work. SELECT 'Hello World' FROM DUAL We can also do math: SELECT 1+1 FROM DUAL And we can run even run functions: SELECT SYSTIMESTAMP FROM DUAL To put all of this together, you can grab all of this data at the same time using commas to separate different columns from our generated table: SELECT 'Hello World', 1+1, SYSTIMESTAMP FROM DUAL Support me on Patreon: http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 32973 Caleb Curry
Part 4   Delete duplicate rows in sql
 
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Link for all dot net and sql server video tutorial playlists http://www.youtube.com/user/kudvenkat/playlists Link for slides, code samples and text version of the video http://csharp-video-tutorials.blogspot.com/2014/05/part-4-delete-duplicate-rows-in-sql.html In this video, we will discuss deleting all duplicate rows except one from a sql server table. SQL Script to create Employees table Create table Employees ( ID int, FirstName nvarchar(50), LastName nvarchar(50), Gender nvarchar(50), Salary int ) GO Insert into Employees values (1, 'Mark', 'Hastings', 'Male', 60000) Insert into Employees values (1, 'Mark', 'Hastings', 'Male', 60000) Insert into Employees values (1, 'Mark', 'Hastings', 'Male', 60000) Insert into Employees values (2, 'Mary', 'Lambeth', 'Female', 30000) Insert into Employees values (2, 'Mary', 'Lambeth', 'Female', 30000) Insert into Employees values (3, 'Ben', 'Hoskins', 'Male', 70000) Insert into Employees values (3, 'Ben', 'Hoskins', 'Male', 70000) Insert into Employees values (3, 'Ben', 'Hoskins', 'Male', 70000) The delete query should delete all duplicate rows except one. Here is the SQL query that does the job. PARTITION BY divides the query result set into partitions. WITH EmployeesCTE AS ( SELECT *, ROW_NUMBER()OVER(PARTITION BY ID ORDER BY ID) AS RowNumber FROM Employees ) DELETE FROM EmployeesCTE WHERE RowNumber ] 1
Views: 366204 kudvenkat
SQL Tutorial - Window Functions
 
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For the best book on T-SQL click here: https://www.amazon.co.uk/gp/product/0735685045/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0735685045&linkCode=as2&tag=beardeddev-21&linkId=2e450454659d4279f54dd188d24bc011 Another fantastic SQL Tutorial brought to you by BeardedDev. In this video we begin to explore Window Functions and their purpose within SQL Server. Window Functions are used for performing data analysis calculations and address an important need compared to the GROUP BY clause that we are able to return the underlying data in the same query. This video shows an example of the differences between the GROUP BY clause and Window Functions. Window Functions were first introduced in SQL Server 2005 but further enhancements and support was added in SQL Server 2012. We look at the OVER clause and PARTITION BY. Window Functions can only be included within SELECT or ORDER BY clauses. Functions Available: Aggregate - COUNT, SUM, MIN, MAX, AVG Offset - FIRST_VALUE, LAST_VALUE, LEAD, LAG Statistical - PERCENT_RANK, CUME_DIST, PERCENTILE_CONT, PERCENTILE_DIST Windows Functions also have FRAMES ROWS RANGE Window Functions are a powerful tool within SQL Server and I am excited to bring more videos and tutorials working with Window Functions in the future. Code: WITH CTE AS ( SELECT Sales_Id , SUM(Line_Total) AS Total FROM Sales_Details GROUP BY Sales_Id ) SELECT * FROM CTE AS A INNER JOIN Sales_Details AS B ON A.Sales_Id = B.Sales_Id SELECT Sales_Id , Sales_Date , Item , Price , Quantity , Line_Total , COUNT(Line_Total) OVER(PARTITION BY Sales_Id) AS Line_Count , SUM(Line_Total) OVER(PARTITION BY Sales_Id) AS Sales_Total , SUM(Line_Total) OVER(PARTITION BY Sales_Date) AS Daily_Total , SUM(Line_Total) OVER() AS Total FROM Sales_Details ORDER BY Sales_Total
Views: 14831 BeardedDev
Oracle Hints Tutorial for improving performance
 
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Oracle Hints Tutorial for improving performance APPEND PARALLEL JOIN INDEX NO_INDEX SELECT /*+ FIRST_ROWS(10) */ * FROM emp WHERE deptno = 10; SELECT /*+ ALL_ROWS */ * FROM emp WHERE deptno = 10; SELECT /*+ NO_INDEX(emp emp_dept_idx) */ * FROM emp, dept WHERE emp.deptno = dept.deptno; SELECT /*+ INDEX(e,emp_dept_idx) */ * FROM emp e WHERE e.deptno = 10; -- SELECT /*+ INDEX(scott.emp,emp_dept_idx) */ * FROM scott.emp; SELECT /*+ AND_EQUAL(e,emp_dept_idx) */ * FROM emp e; SELECT /*+ INDEX_JOIN(e,emp_dept_idx) */ * FROM emp e; SELECT /*+ PARALLEL_INDEX(e,emp_dept_idx , 8) */ * FROM emp e; SELECT /*+ LEADING (dept) */ * FROM emp, dept WHERE emp.deptno = dept.deptno; SELECT /*+ PARALLEL(8) CACHE (e) FULL (e) */ * FROM emp e ; SELECT /*+ PARALLEL FULL (e) */ * FROM emp e ; SELECT /*+ PARALLEL USE_MERGE (emp dept) */ * FROM emp, dept WHERE emp.deptno = dept.deptno; -- SORT Merge Join SELECT /*+ PARALLEL USE_HASH (emp dept) */ * FROM emp, dept WHERE emp.deptno = dept.deptno; -- Hash Join SELECT /*+ PARALLEL */ * FROM emp e ; INSERT /*+ APPEND */ INTO mytmp select /*+ CACHE (e) */ *from emp e; commit;
Views: 10277 TechLake
Row Number function in SQL Server
 
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sql server row_number example sql server row number by partition sql server row_number over partition by order by In this video we will discuss Row_Number function in SQL Server. This is continuation to Part 108. Please watch Part 108 from SQL Server tutorial before proceeding. Row_Number function Introduced in SQL Server 2005 Returns the sequential number of a row starting at 1 ORDER BY clause is required PARTITION BY clause is optional When the data is partitioned, row number is reset to 1 when the partition changes Syntax : ROW_NUMBER() OVER (ORDER BY Col1, Col2) Row_Number function without PARTITION BY : In this example, data is not partitioned, so ROW_NUMBER will provide a consecutive numbering for all the rows in the table based on the order of rows imposed by the ORDER BY clause. SELECT Name, Gender, Salary, ROW_NUMBER() OVER (ORDER BY Gender) AS RowNumber FROM Employees Please note : If ORDER BY clause is not specified you will get the following error The function 'ROW_NUMBER' must have an OVER clause with ORDER BY Row_Number function with PARTITION BY : In this example, data is partitioned by Gender, so ROW_NUMBER will provide a consecutive numbering only for the rows with in a parttion. When the partition changes the row number is reset to 1. SELECT Name, Gender, Salary, ROW_NUMBER() OVER (PARTITION BY Gender ORDER BY Gender) AS RowNumber FROM Employees Use case for Row_Number function : Deleting all duplicate rows except one from a sql server table. Discussed in detail in Part 4 of SQL Server Interview Questions and Answers video series. Text version of the video http://csharp-video-tutorials.blogspot.com/2015/09/rownumber-function-in-sql-server.html Slides http://csharp-video-tutorials.blogspot.com/2015/09/rownumber-function-in-sql-server_30.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 90392 kudvenkat
Oracle SQL: Using the select statement by AskTheOracle.net
 
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Learn the basics of the Oracle SQL SELECT statement in just a few minutes - including how to select multiple columns, how to restrict the rows retrieved and how to change the values of columns as you retrieve them. For more Oracle tutorials, see our website at http://www.asktheoracle.net
Views: 1056 asktheoracle1
Rank and Dense Rank in SQL Server
 
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rank and dense_rank example difference between rank and dense_rank with example rank vs dense_rank in sql server 2008 sql server difference between rank and dense_rank In this video we will discuss Rank and Dense_Rank functions in SQL Server Rank and Dense_Rank functions Introduced in SQL Server 2005 Returns a rank starting at 1 based on the ordering of rows imposed by the ORDER BY clause ORDER BY clause is required PARTITION BY clause is optional When the data is partitioned, rank is reset to 1 when the partition changes Difference between Rank and Dense_Rank functions Rank function skips ranking(s) if there is a tie where as Dense_Rank will not. For example : If you have 2 rows at rank 1 and you have 5 rows in total. RANK() returns - 1, 1, 3, 4, 5 DENSE_RANK returns - 1, 1, 2, 3, 4 Syntax : RANK() OVER (ORDER BY Col1, Col2, ...) DENSE_RANK() OVER (ORDER BY Col1, Col2, ...) RANK() and DENSE_RANK() functions without PARTITION BY clause : In this example, data is not partitioned, so RANK() function provides a consecutive numbering except when there is a tie. Rank 2 is skipped as there are 2 rows at rank 1. The third row gets rank 3. DENSE_RANK() on the other hand will not skip ranks if there is a tie. The first 2 rows get rank 1. Third row gets rank 2. SELECT Name, Salary, Gender, RANK() OVER (ORDER BY Salary DESC) AS [Rank], DENSE_RANK() OVER (ORDER BY Salary DESC) AS DenseRank FROM Employees RANK() and DENSE_RANK() functions with PARTITION BY clause : Notice when the partition changes from Female to Male Rank is reset to 1 SELECT Name, Salary, Gender, RANK() OVER (PARTITION BY Gender ORDER BY Salary DESC) AS [Rank], DENSE_RANK() OVER (PARTITION BY Gender ORDER BY Salary DESC) AS DenseRank FROM Employees Use case for RANK and DENSE_RANK functions : Both these functions can be used to find Nth highest salary. However, which function to use depends on what you want to do when there is a tie. Let me explain with an example. If there are 2 employees with the FIRST highest salary, there are 2 different business cases 1. If your business case is, not to produce any result for the SECOND highest salary, then use RANK function 2. If your business case is to return the next Salary after the tied rows as the SECOND highest Salary, then use DENSE_RANK function Since we have 2 Employees with the FIRST highest salary. Rank() function will not return any rows for the SECOND highest Salary. WITH Result AS ( SELECT Salary, RANK() OVER (ORDER BY Salary DESC) AS Salary_Rank FROM Employees ) SELECT TOP 1 Salary FROM Result WHERE Salary_Rank = 2 Though we have 2 Employees with the FIRST highest salary. Dense_Rank() function returns, the next Salary after the tied rows as the SECOND highest Salary WITH Result AS ( SELECT Salary, DENSE_RANK() OVER (ORDER BY Salary DESC) AS Salary_Rank FROM Employees ) SELECT TOP 1 Salary FROM Result WHERE Salary_Rank = 2 You can also use RANK and DENSE_RANK functions to find the Nth highest Salary among Male or Female employee groups. The following query finds the 3rd highest salary amount paid among the Female employees group WITH Result AS ( SELECT Salary, Gender, DENSE_RANK() OVER (PARTITION BY Gender ORDER BY Salary DESC) AS Salary_Rank FROM Employees ) SELECT TOP 1 Salary FROM Result WHERE Salary_Rank = 3 AND Gender = 'Female' Text version of the video http://csharp-video-tutorials.blogspot.com/2015/10/rank-and-denserank-in-sql-server.html Slides http://csharp-video-tutorials.blogspot.com/2015/10/rank-and-denserank-in-sql-server_1.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 84241 kudvenkat
SQL: Group By,  Having, Min, Max Sum
 
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Learn to summarize yoru data using the SQL Aggregates such as count and sum and the GROUP BY and HAVING clauses of the SELECT statement
Views: 159042 Michael Fudge
HOW TO IDENTIFY AND DELETE DUPLICATE ROWS USING ROWID AND GROUPBY IN ORACLE SQL
 
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This video demonstrates examples on how to find and delete duplicate records from a table. The video gives simple and easy to understand examples on finding duplicate records from a table using group by and having clause and row_number function. It also shows the ways in which duplicates can be deleted very efficiently using the rowid of that record. You can get the code from our website http://oracleplsqlblog.com/FullBlog/FullBlog/21
Views: 11906 Kishan Mashru
how to get highest salary in each department
 
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highest salary in each department oracle highest salary in each department sql highest salary in each department db2 How to select highest salary from each department how to get highest salary in each department sql server interview questions answers
Views: 4936 DotNet Techy
HAVING clause and difference with GROUP BY & WHERE clause in SQL statement
 
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Using HAVING clause and difference with GROUP BY & WHERE clause in SQL statement Link for scripts on my blog: https://sqlwithmanoj.com/2015/05/23/sql-basics-difference-between-where-group-by-and-having-clause/ Check the whole "SQL Server Basics" series here: https://www.youtube.com/playlist?list=PLU9JMEzjCv14f3cWDhubPaddxRvx1reKR Check my SQL blog at: http://sqlwithmanoj.com/ Check my SQL FB Page at: https://www.facebook.com/sqlwithmanoj
Views: 75093 SQL with Manoj
Find Duplicate Rows in SQL - Select Statement Tutorial
 
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Find duplicate row values in a field or multiple fields in SQL Server table with this tutorial. Do this for one column, or multiple columns. Uses SQL Server Management Studio for the demonstration.
Views: 48271 Edward Kench
Oracle Partitioning
 
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Oracle Partitioning watch more videos at https://www.tutorialspoint.com/videotutorials/index.htm Lecture By: Mr. Parth Panjab, Tutorials Point India Private Limited
ROWID VS ROWNUM IN ORACLE
 
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This Video explains the difference between ROWID and ROWNUM using real project examples. ROWID provides the unique physical address where the row is being stored. ROWNUM indicates the order in which the data was returned from the select query.
Views: 4235 Tech Coach
Leaner, Faster Code with Advanced SQL Techniques
 
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Connor Mcdonald, Developer Advocate for SQL, Oracle Most SQL is so simple to write that we can hand off the job to an ORM tool or a similar mechanism. But by delving a little deeper into more-advanced SQL facilities, we can get performance benefits and write a lot less middle-tier code. This session highlights some SQL techniques for solving problems that would otherwise require a lot of complex coding. Learn how to become a more productive developer by expanding your knowledge of the SQL language.
Views: 8205 Oracle Developers
Does partitioning Improve performance ? Explained
 
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Partitioning is a great feature for improving the way we manage our data. However we can also improve performance of select statements from the table as well. This requires a good understanding of the way partitioning works and how properly placing files on the disk can improve the IO performance. One common way that partitioning can improve performance for loading data is the sliding window method but in this post I am mainly talking about how to improve read performance. Before showing the improvements from partitioning it’s important to visit the indexes since a common belief is that a good index can provide faster data access than partitioning can.
Views: 1284 Jayanth Kurup
SQL TOP, RANK, DENSE_RANK, ROW_NUMBER Functions
 
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Jamie King of Neumont University demonstrating various SQL ranking functions.
Views: 24027 Jamie King
SQL tutorial 62: Indexes In Oracle Database By Manish Sharma RebellionRider
 
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Watch and learn concepts of SQL Index In Oracle Database. In this tutorial you will learn about B-Tree Index and Function based Index. ------------------------------------------------------------------------ ►►►LINKS◄◄◄ Blog : Previous Tutorial ► ------------------------------------------------------------------------- ►►►Help Me In Getting A Job◄◄◄ ►Help Me In Getting A Good Job By Connecting With Me on My LinkedIn and Endorsing My Skills. All My Contact Info is Down Below. You Can Also Refer Me To Your Company Thanks ------------------------------------------------------------------------- Copy Cloud referral link || Use this link to join copy cloud and get 20GB of free storage https://copy.com?r=kb4rc1 -------------------------------------------------------------------------- ►Make sure you SUBSCRIBE and be the 1st one to see my videos! -------------------------------------------------------------------------- Amazon Wishlist: http://bit.ly/wishlist-amazon ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ►►►Find me on Social Media◄◄◄ Follow What I am up to as it happens on https://twitter.com/rebellionrider https://www.facebook.com/imthebhardwaj http://instagram.com/rebellionrider https://plus.google.com/+Rebellionrider http://in.linkedin.com/in/mannbhardwaj/ http://rebellionrider.tumblr.com/ http://www.pinterest.com/rebellionrider/ You can also Email me at for E-mail address please check About section Please please LIKE and SHARE my videos it makes me happy. Thanks for liking, commenting, sharing and watching more of our videos This is Manish from RebellionRider.com ♥ I LOVE ALL MY VIEWERS AND SUBSCRIBERS
Views: 43376 Manish Sharma
Optimizing SQL Performance
 
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Held on July 12 2018 In July's session we mainly looked at performance. Highlights include: 1:30 How does the database process subqueries? 5:20 Performance: comparing insert ... select to create tmp table, insert select from tmp; DDL in PL/SQL; dynamic SQL problems 12:45 18c private temporary tables; tables specific to a session; DDL you can rollback across! 21:00 Improving update performance: things to watch for; insert vs. update; "join-update" - create a view instead; create table as select "update" 34:05 Analytic function performance: first_value non-determinism; min keep vs first_value; computing function in a subquery; indexes for analytic functions AskTOM Office Hours offers free, monthly training and tips on how to make the most of Oracle Database, from Oracle product managers, developers and evangelists. https://asktom.oracle.com/ Oracle Developers portal: https://developer.oracle.com/ Sign up for an Oracle Cloud trial: https://cloud.oracle.com/en_US/tryit music: bensound.com
Views: 745 Oracle Developers
Oracle SQL Developer Tutorial For Beginners   17   Selecting Particular Columns
 
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Oracle SQL Developer Tutorial For Beginners Series. This course introduces Oracle SQL Development for its subscribers. Currently this is based on Oracle 12c. The test environment is in Windows 10.
Views: 2741 Sam Dhanasekaran
NTILE function in SQL Server
 
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In this video we will discuss NTILE function in SQL Server NTILE function 1. Introduced in SQL Server 2005 2. ORDER BY Clause is required 3. PARTITION BY clause is optional 4. Distributes the rows into a specified number of groups 5. If the number of rows is not divisible by number of groups, you may have groups of two different sizes. 6. Larger groups come before smaller groups For example NTILE(2) of 10 rows divides the rows in 2 Groups (5 in each group) NTILE(3) of 10 rows divides the rows in 3 Groups (4 in first group, 3 in 2nd & 3rd group) Syntax : NTILE (Number_of_Groups) OVER (ORDER BY Col1, Col2, ...) SQL Script to create Employees table Create Table Employees ( Id int primary key, Name nvarchar(50), Gender nvarchar(10), Salary int ) Go Insert Into Employees Values (1, 'Mark', 'Male', 5000) Insert Into Employees Values (2, 'John', 'Male', 4500) Insert Into Employees Values (3, 'Pam', 'Female', 5500) Insert Into Employees Values (4, 'Sara', 'Female', 4000) Insert Into Employees Values (5, 'Todd', 'Male', 3500) Insert Into Employees Values (6, 'Mary', 'Female', 5000) Insert Into Employees Values (7, 'Ben', 'Male', 6500) Insert Into Employees Values (8, 'Jodi', 'Female', 7000) Insert Into Employees Values (9, 'Tom', 'Male', 5500) Insert Into Employees Values (10, 'Ron', 'Male', 5000) Go NTILE function without PARTITION BY clause : Divides the 10 rows into 3 groups. 4 rows in first group, 3 rows in the 2nd & 3rd group. SELECT Name, Gender, Salary, NTILE(3) OVER (ORDER BY Salary) AS [Ntile] FROM Employees What if the specified number of groups is GREATER THAN the number of rows NTILE function will try to create as many groups as possible with one row in each group. With 10 rows in the table, NTILE(11) will create 10 groups with 1 row in each group. SELECT Name, Gender, Salary, NTILE(11) OVER (ORDER BY Salary) AS [Ntile] FROM Employees NTILE function with PARTITION BY clause : When the data is partitioned, NTILE function creates the specified number of groups with in each partition. The following query partitions the data into 2 partitions (Male & Female). NTILE(3) creates 3 groups in each of the partitions. SELECT Name, Gender, Salary, NTILE(3) OVER (PARTITION BY GENDER ORDER BY Salary) AS [Ntile] FROM Employees Link for all dot net and sql server video tutorial playlists https://www.youtube.com/user/kudvenkat/playlists?sort=dd&view=1 Link for slides, code samples and text version of the video http://csharp-video-tutorials.blogspot.com/2015/10/ntile-function-in-sql-server.html
Views: 41546 kudvenkat
Table Partitioning in Oracle Sql | Oracle Sql Partitioning | Oracle Sql Partitioning Step by Step
 
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Table Partitioning in Oracle Sql | Oracle Sql Partitioning | Oracle Sql Partitioning Step by Step --------------------------------------------------------------------------------------------------------- oracle, partition, partitioning, sql, partitioning in oracle, hash, list, range, interval partition, reference partition, composite partition, index partition, performance, partition pruning, partition wise join, sql server, partition table, sql server table partitioning, table partitioning, sql server partitioning, sql server table partition, table partition, what is partition, partitioned table, advantages of partition, types of partitions, ,table partitioning in sql server 2012 step by step,table partitioning in sql server 2014 step by step,table partitioning in sql server 2016 step by step,partition table sql server 2012 example,sql server partition existing table,sql server partition table by month,table partitioning in sql server 2008 r2 step by step,sql server partitioning best practices,horizontal partitioning in sql server, sql tutorials for beginners, sql expert, sql expert tutorials, database, oracle, table, online training,insert into oracle,oracle insert into multiple rows,create table oracle,oracle 12c alter table add identity column,oracle create table default value sysdate,collections in oracle pl sql with examples,Oracle 12c, database, oracle database (software), sql, sql developer, sql tutorials, how to create database using dbca, how to create database in oracle,oracle cloud, database 12c, dba genesis,database services, database, create, 11g, dba, db, beginner, Please Subscribe My Channel Composite Range-Range Partitioning Composite range-range partitioning enables logical range partitioning along two dimensions; for example, partition by order_date and range subpartition by shipping_date. Composite Range-Hash Partitioning Composite range-hash partitioning partitions data using the range method, and within each partition, subpartitions it using the hash method. Composite range-hash partitioning provides the improved manageability of range partitioning and the data placement, striping, and parallelism advantages of hash partitioning. Composite Range-List Partitioning Composite range-list partitioning partitions data using the range method, and within each partition, subpartitions it using the list method. Composite range-list partitioning provides the manageability of range partitioning and the explicit control of list partitioning for the subpartitions. Composite List-Range Partitioning Composite list-range partitioning enables logical range subpartitioning within a given list partitioning strategy; for example, list partition by country_id and range subpartition by order_date. Composite List-Hash Partitioning Composite list-hash partitioning enables hash subpartitioning of a list-partitioned object; for example, to enable partition-wise joins. Composite List-List Partitioning Composite list-list partitioning enables logical list partitioning along two dimensions; for example, list partition by country_id and list subpartition by sales_channel. Composite Hash-Hash Partitioning Composite hash-hash partitioning enables hash partitioning along two dimensions. This technique is beneficial to enable partition-wise joins along two dimensions. Composite Hash-List Partitioning Composite hash-list partitioning enables hash partitioning along two dimensions. Composite Hash-Range Partitioning Composite hash-range partitioning enables hash partitioning along two dimensions.
Oracle SQL Developer Tutorial For Beginners  75   SELECT PARTICULAR COLUMNS
 
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Oracle SQL Developer Tutorial For Beginners Series. This course introduces Oracle SQL Development for its subscribers. Currently this is based on Oracle 12c. The test environment is in Windows 10.
Views: 700 Sam Dhanasekaran
Difference between Row Number, Rank and Dense Rank | Oracle SQL Tutorial | Mr.Murali
 
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►For Registration : https://goo.gl/r6kJbB ►Call: +91-8179191999 ► Visit Our Website: http://nareshit.in/ http://nareshit.com/ ► About NareshIT: "Naresh IT is the Best Software Training Institute for Hadoop, Salesforce, AWS, DevOps, Sprak, Data Science, Python, Tableau, RPA ,Java, C#.NET, ASP.NET, Oracle, Testing Tools, Silver light, Linq, SQL Server, Selenium, Android, iPhone, C Language, C++, PHP and Digital Marketing in Hyderabad, Chennai and Vijayawada, India which provides online and classroom training classes" ►For Registration : https://goo.gl/r6kJbB ►Call: India- 8179191999, USA- 404-232-9879 Email: [email protected] ►Our Online Training Features: 1.Training with Real-Time Experts 2.Industry Specific Scenario’s 3.Flexible Timings 4.Soft Copy of Material 5.Share Video's of each and every session. Check The Below Links: ►For Course Reg : https://goo.gl/r6kJbB ► Subscribe to Our Channel: https://goo.gl/q9ozyG ► Circle us on G+: https://plus.google.com/NareshIT ► Like us on Facebook: https://www.facebook.com/NareshIT ► Follow us on Twitter: https://twitter.com/nareshitech ► Visit Our Website: http://nareshit.in/ http://nareshit.com/
Views: 12392 Naresh i Technologies
SQL: Views
 
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This SQL screen cast will introduce the viewer to SQL views. You will learn how to create your own views in SQL, find them in the INFORMATION_SCHEMA, and alter their contents. Querying the view using the select statement will be demonstrated.
Views: 114125 Michael Fudge
Dynamic sql table name variable
 
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Text version of the video http://csharp-video-tutorials.blogspot.com/2017/04/dynamic-sql-table-name-variable.html Slides http://csharp-video-tutorials.blogspot.com/2017/04/dynamic-sql-table-name-variable_20.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All SQL Server Tutorial Videos https://www.youtube.com/playlist?list=PL08903FB7ACA1C2FB All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists In this video we will discuss how to pass table name dynamically for stored procedure in sql server. This is one of the sql questions that is very commonly asked. I have a web page with a textbox. When I enter a table name in the textbox and when I click "Load Data" button, we want to retrieve data from that respective table and display it on the page. Copy the SQL Script to create the tables from my blog using the link below http://csharp-video-tutorials.blogspot.com/2017/04/dynamic-sql-table-name-variable.html Create the following stored procedure. Notice we are passing table name as a parameter to the stored prcoedure. In the body of the stored procedure we are concatenating strings to build our dynamic sql statement. In our previous videos we discussed that this open doors for SQL injection. Create procedure spDynamicTableName @TableName nvarchar(100) As Begin Declare @sql nvarchar(max) Set @sql = 'Select * from ' + @TableName Execute sp_executesql @sql End So the obvious question that comes to our mind is, why are we not creating parameterised sql statement instead. The answers is we can't. SQL Server does not allow table names and column names to be passed as parameters. Notice in the example below, we are creating a parameterised query with @TabName as a parameter. When we execute the following code, the procedure gets created successfully. Create procedure spDynamicTableName1 @TableName nvarchar(100) As Begin Declare @sql nvarchar(max) Set @sql = 'Select * from @TabName' Execute sp_executesql @sql, N'@TabName nvarchar(100)', @TabName = @TableName End But when we try to execute it we get an error - Must declare the table variable "@TabName" Execute spDynamicTableName1 N'Countries' Add a Web Page to the project that we have been working with in our previous video. Name it "DynamicTableName.aspx". Copy and paste the HTML from my blog using the link below http://csharp-video-tutorials.blogspot.com/2017/04/dynamic-sql-table-name-variable.html Copy and paste the code from my blog in the code-behind page http://csharp-video-tutorials.blogspot.com/2017/04/dynamic-sql-table-name-variable.html At this point, run the application and type the following text in the "Table Name" textbox and click "Load Data" button. Notice "SalesDB" database is dropped. Our application is prone to SQL injection as we have implemented dynamic sql in our stored procedure by concatenating strings instead of using parameters. Employees; Drop database SalesDB One way to prevent SQL injection in this case is by using SQL Server built-in function - QUOTENAME(). We will discuss QUOTENAME() function in detail in our next video. For now understand that by default, this function wraps that string that is passed to it in a pair of brackets. SELECT QUOTENAME('Employees') returns [Employees] Modify the stored procedure to use QUOTENAME() function as shown below. Alter procedure spDynamicTableName @TableName nvarchar(100) As Begin Declare @sql nvarchar(max) Set @sql = 'Select * from ' + QUOTENAME(@TableName) Execute sp_executesql @sql End At this point, type the following text in the "Table Name" textbox and click "Load Data" button. Notice you will see a message - Invalid object name 'Employees; Drop database SalesDB'. Also "SalesDB" database is not dropped. Employees; Drop database SalesDB The entire text in "Table Name" textbox is wrapped in a pair of brackets by the QUOTENAME function and is treated as table name. Since we do have a table with the specified name, we get the error - Invalid object name.
Views: 29959 kudvenkat
Explain Ranking Function and RowNumber in SQL Server
 
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SQL server row_number example SQL server row number by partition SQL server row_number over partition by order by In this video, we will discuss Row_Number function in SQL Server. Row_Number function Returns the sequential number of a row starting at 1 ORDER BY clause is required PARTITION BY clause is optional When the data is partitioned, the row number is reset to 1 when the partition changes Syntax : ROW_NUMBER() OVER (ORDER BY Col1, Col2) Row_Number function without PARTITION By: In this example, data is not partitioned so ROW_NUMBER will provide a consecutive numbering for all the rows in the table based on the order of rows imposed by the ORDER BY clause. SELECT Name, Gender, Salary, ROW_NUMBER() OVER (ORDER BY Gender) AS RowNumber FROM Employees Please note: If ORDER BY clause is not specified you will get the following error The function 'ROW_NUMBER' must have an OVER clause with ORDER BY Row_Number function with PARTITION BY : In this example, data is partitioned by Gender so ROW_NUMBER will provide a consecutive numbering only for the rows within a partition. When the partition changes the row number is reset to 1. SELECT Name, Gender, Salary, ROW_NUMBER() OVER (PARTITION BY Gender ORDER BY Gender) AS RowNumber FROM Employees Use case for Row_Number function: Deleting all duplicate rows except one from a SQL server table.
Lead and Lag functions in SQL Server 2012
 
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In this video we will discuss about Lead and Lag functions. Lead and Lag functions Introduced in SQL Server 2012 Lead function is used to access subsequent row data along with current row data Lag function is used to access previous row data along with current row data ORDER BY clause is required PARTITION BY clause is optional Syntax LEAD(Column_Name, Offset, Default_Value) OVER (ORDER BY Col1, Col2, ...) LAG(Column_Name, Offset, Default_Value) OVER (ORDER BY Col1, Col2, ...) Offset - Number of rows to lead or lag. Default_Value - The default value to return if the number of rows to lead or lag goes beyond first row or last row in a table or partition. If default value is not specified NULL is returned. We will use the following Employees table for the examples in this video SQL Script to create the Employees table Create Table Employees ( Id int primary key, Name nvarchar(50), Gender nvarchar(10), Salary int ) Go Insert Into Employees Values (1, 'Mark', 'Male', 1000) Insert Into Employees Values (2, 'John', 'Male', 2000) Insert Into Employees Values (3, 'Pam', 'Female', 3000) Insert Into Employees Values (4, 'Sara', 'Female', 4000) Insert Into Employees Values (5, 'Todd', 'Male', 5000) Insert Into Employees Values (6, 'Mary', 'Female', 6000) Insert Into Employees Values (7, 'Ben', 'Male', 7000) Insert Into Employees Values (8, 'Jodi', 'Female', 8000) Insert Into Employees Values (9, 'Tom', 'Male', 9000) Insert Into Employees Values (10, 'Ron', 'Male', 9500) Go Lead and Lag functions example WITHOUT partitions : This example Leads 2 rows and Lags 1 row from the current row. When you are on the first row, LEAD(Salary, 2, -1) allows you to move forward 2 rows and retrieve the salary from the 3rd row. When you are on the first row, LAG(Salary, 1, -1) allows us to move backward 1 row. Since there no rows beyond row 1, Lag function in this case returns the default value -1. When you are on the last row, LEAD(Salary, 2, -1) allows you to move forward 2 rows. Since there no rows beyond the last row 1, Lead function in this case returns the default value -1. When you are on the last row, LAG(Salary, 1, -1) allows us to move backward 1 row and retrieve the salary from the previous row. SELECT Name, Gender, Salary, LEAD(Salary, 2, -1) OVER (ORDER BY Salary) AS Lead_2, LAG(Salary, 1, -1) OVER (ORDER BY Salary) AS Lag_1 FROM Employees Lead and Lag functions example WITH partitions : Notice that in this example, Lead and Lag functions return default value if the number of rows to lead or lag goes beyond first row or last row in the partition. SELECT Name, Gender, Salary, LEAD(Salary, 2, -1) OVER (PARTITION By Gender ORDER BY Salary) AS Lead_2, LAG(Salary, 1, -1) OVER (PARTITION By Gender ORDER BY Salary) AS Lag_1 FROM Employees Text version of the video http://csharp-video-tutorials.blogspot.com/2015/10/lead-and-lag-functions-in-sql-server.html Slides http://csharp-video-tutorials.blogspot.com/2015/10/lead-and-lag-functions-in-sql-server_5.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 55082 kudvenkat
Why Table Partitioning Doesn't Speed Up Query Performance
 
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Learn why SQL Server's table partitioning feature doesn't make your queries faster-- and may even make them slower. In this 20 minute video, I'll show you my favorite articles, bugs, and whitepapers online to explain where table partitioning shines and why you might want to implement it, even though it won't solve your query performance problems. Articles discussed are by Gail Shaw, Remus Rusanu, and the SQL Customer Advisory Team (SQLCAT). Get URLs to each article here: http://www.littlekendra.com/2016/05/03/why-table-partitioning-doesnt-speed-up-query-performance-video/
GROUP BY with Aggregate functions in SQL statement
 
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Using "GROUP BY" clause with Aggregate functions in SQL statement Check the whole "SQL Server Basics" series here: https://www.youtube.com/playlist?list=PLU9JMEzjCv14f3cWDhubPaddxRvx1reKR Check my SQL blog at: http://sqlwithmanoj.com/ Check my SQL FB Page at: https://www.facebook.com/sqlwithmanoj
Views: 46872 SQL with Manoj
ORACLE SQL AND PL/SQL INTERVIEW QUESTION : DIFFERENCE BETWEEN ROWID AND ROWNUM WITH EXAMPLE
 
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In this video tutorial, we discuss the pseudo column rowid and rownum in oracle sql. After watching this video you would be able to understand the basic difference between rowid and a rownum pseudo columns of oracle database. Rowid returns the exact location of the row in the database, hence whenever you retrive a record based on rowid, it is the fastest retrival possible. Whereas for each row returned by a query, the ROWNUM pseudocolumn returns a number indicating the order in which Oracle selects the row from a table or set of joined rows. For more such videos visit out complete list of videos on www.youtube.com/c/kishanmashru Visit or blog www.oracleplsqlblog.com
Views: 2013 Kishan Mashru
NULL Value in Oracle Database | Oracle Tutorials for Beginners
 
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NULL Value in Oracle Database | Oracle Tutorials for Beginners NULL Value in Oracle Database NULL Value in Oracle SQL NULL Value in SQL NULL Value in Oracle Database Oracle Tutorials for Beginners Oracle Tutorials for Beginners Oracle PL/SQL Tutorials for Beginners Oracle PL/SQL Tutorials for Beginners Oracle PL/SQL Tutorials for Beginners how to select null values in oracle oracle compare null values in where clause null=null in oracle how to handle null in case statement in oracle how to check null value in oracle stored procedure oracle nvl null value in oracle query how to check empty column value in oracle how to select null values in oracle oracle is null vs = null oracle nvl oracle is not null oracle decode oracle isnull oracle case when null select null from table in oracle oracle compare null values in where clause oracle select null how to check empty column value in oracle oracle sql not null or empty oracle is not null how to handle null in case statement in oracle oracle isnull oracle nvl
Views: 870 Oracle PL/SQL World
Lec-47: SQL Queries and Subqueries (part-1) | Database Management System
 
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Please Like, Subscribe the channel and give your valuable feedback. Need your Support.. Lecture By: Mr. Varun Singla Facebook page link : https://www.facebook.com/gatesmashers/ #Subqueries#SqlDBMS#freeEducationGATE
Views: 178409 Gate Smashers
How to Choose the Right Database? - MongoDB, Cassandra, MySQL, HBase - Frank Kane
 
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Explore the full course on Udemy (special discount included in the link): https://www.udemy.com/the-ultimate-hands-on-hadoop-tame-your-big-data/?couponCode=HADOOPUYT Choosing the right database for your application is no easy task. You have a wide variety of options relational databases such as MySQL, or distributed NoSQL solutions such as MongoDB, Cassandra, and HBase. NoSQL has come to mean not only SQL as many distributed database systems do in fact support SQL-style queries, as long as you are not doing complex join operations and this further blurs the lines between these systems. We will talk about how to analyze the requirements of your system in terms of consistency, availability, and partition-tolerance, and how to apply the CAP theorem to guide your choice after showing you where different database technologies fall on the sides of the CAP triangle. We will also talk about more practical considerations, such as your budget, need for professional support, and the ease of integration into the other systems already in place in your organization. Maybe you dont even need a distributed storage solution at all! Choosing the right technology for your data storage will save you a lot of pain as your application grows and evolves and making the wrong choice can lead to all sorts of maintenance problems and wasted work. Your instructor is Frank Kane of Sundog Education, bringing nine years of experience as a senior engineer and senior manager at Amazon.com and IMDb.com, where his job involved extracting meaning from their massive data sets, and processing that data in a highly distributed manner.
Views: 41328 Udemy Tech
Calculate running total in SQL Server 2012
 
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running total sql server cumulative total in ms sql server running total column In this video we will discuss how to calculate running total in SQL Server 2012 and later versions. We will use the following Employees table for the examples in this video. SQL Script to create Employees table Create Table Employees ( Id int primary key, Name nvarchar(50), Gender nvarchar(10), Salary int ) Go Insert Into Employees Values (1, 'Mark', 'Male', 5000) Insert Into Employees Values (2, 'John', 'Male', 4500) Insert Into Employees Values (3, 'Pam', 'Female', 5500) Insert Into Employees Values (4, 'Sara', 'Female', 4000) Insert Into Employees Values (5, 'Todd', 'Male', 3500) Insert Into Employees Values (6, 'Mary', 'Female', 5000) Insert Into Employees Values (7, 'Ben', 'Male', 6500) Insert Into Employees Values (8, 'Jodi', 'Female', 7000) Insert Into Employees Values (9, 'Tom', 'Male', 5500) Insert Into Employees Values (10, 'Ron', 'Male', 5000) Go SQL Query to compute running total without partitions SELECT Name, Gender, Salary, SUM(Salary) OVER (ORDER BY ID) AS RunningTotal FROM Employees SQL Query to compute running total with partitions SELECT Name, Gender, Salary, SUM(Salary) OVER (PARTITION BY Gender ORDER BY ID) AS RunningTotal FROM Employees What happens if I use order by on Salary column If you have duplicate values in the Salary column, all the duplicate values will be added to the running total at once. In the example below notice that we have 5000 repeated 3 times. So 15000 (i.e 5000 + 5000 + 5000) is added to the running total at once. SELECT Name, Gender, Salary, SUM(Salary) OVER (ORDER BY Salary) AS RunningTotal FROM Employees So when computing running total, it is better to use a column that has unique data in the ORDER BY clause. Text version of the video http://csharp-video-tutorials.blogspot.com/2015/10/calculate-running-total-in-sql-server.html Slides http://csharp-video-tutorials.blogspot.com/2015/10/calculate-running-total-in-sql-server_3.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 60362 kudvenkat