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.

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40 thoughts on “Row Number function in SQL Server

  1. Is there a way to get a rownumber, by gender, such that all in one gender is 1 and the next gender all has a rownumber of two and if there was a third gender then it would all be 3? This isn't really a rownumber anymore but a grouping number to show which 'gender' we are processing.

  2. Hey, Kudvenkat. Just want to leave a message to you. Your tutorial is the best I've ever seen. Thank you so much!

  3. Thank you Venkat. You are helping me a lot. Please make a video how we can rollback our database to a given point.

  4. me si sirvio bastante, a pesar de estar en ingles , logre enteder la idea del ROW NUMBER . Muchas gracias

  5. Hi, thanks for the video, this seems like a very simple function, i have tried it and it seems like its working by its actually returning an empty column, this is my exact code: ROW_NUMBER() OVER (PARTITION BY orddet_nl.invnum ORDER BY orddet_nl.invnum ASC) AS LineReference,

    i dont get any error messages or anything, but it just brings an empty column, any ideas why?

    Thanks

  6. Great video. Could you also use Row_Number as a means to replace a cursor? How would that effect query performance?

  7. I am using SQL community version 5.5.57, Could you please tell me why i am getting below error? Thanks in advance:)

    mysql> select * from userinfo;
    +———+———-+———+
    | loginId | password | access |
    +———+———-+———+
    | z011111 | A1 | User |
    | z021720 | ram99 | Manager |
    | z021721 | demo | User |
    +———+———-+———+
    5 rows in set (0.00 sec)

    mysql> select *, row_number() over(order by loginId) as rowNumber from userinfo;
    ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '(order by loginId) as rowNumber from userinfo' at line 1

  8. GREAT TEACHER! I have been using your videos to reference SQL where I have no clues. Thanks for all your hard works!

  9. Row number rules ! And Venkat rules! You are the best teacher on youtube and in the whole world. I saw all your videos from SQL Server tutorial. Thank U for educating community! God bless you.

  10. Really well explained. Thank you. I really appreciate that you explained the use of it, more people should add that 'cause it's not always clear.

  11. Hi Venkat,

    I have data that has following rows….

    2934046 Kellogg’s Share Your Breakfast 74672 2407522 Kellogg?s Share Your Breakfast ACTIVE 2015-09-01 9999-12-31
    2934046 Kellogg?s Share Your Breakfast 74672 2407522 Kellogg?s Share Your Breakfast ACTIVE 2015-09-01 9999-12-31

    You can see that both rows are the same except for the question mark in the second row. I have to remove such rows from my table. I was trying to use row_number for this, but it doesn't work. Is there any way i can rank such rows based on the characters in my second column…

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