How do I use ROW NUMBER

Question

I want to use the ROW NUMBER   to get      To get the max ROW NUMBER    --  Or i guess this would also be the count of all rows   I tried doing   SELECT max ROW NUMBER   OVER ORDER BY UserId   FROM Users   but it didn t seem to work      To get ROW NUMBER   using a given piece of information  ie  if I have a name and I want to know what row the name came from    I assume it would be something similar to what I tried for  1  SELECT ROW NUMBER   OVER ORDER BY UserId  From Users WHERE UserName  Joe    but this didn t work either     Any Ideas

User · Answer

Though I agree with others that you could use count() to get the total number of rows, here is how you can use the row_count():

To get the total no of rows:

with temp as (
    select row_number() over (order by id) as rownum
    from table_name 
)
select max(rownum) from temp

To get the row numbers where name is Matt:

with temp as (
    select name, row_number() over (order by id) as rownum
    from table_name
)
select rownum from temp where name like 'Matt'

You can further use min(rownum) or max(rownum) to get the first or last row for Matt respectively.

These were very simple implementations of row_number(). You can use it for more complex grouping. Check out my response on Advanced grouping without using a sub query

User · Answer

If you need to return the table s total row count  you can use an alternative way to the SELECT COUNT    statement   Because SELECT COUNT    makes a full table scan to return the row count  it can take very long time for a large table  You can use the sysindexes system table instead in this case  There is a ROWS column that contains the total row count for each table in your database  You can use the following select statement   SELECT rows FROM sysindexes WHERE id   OBJECT ID  table name   AND indid  lt  2   This will drastically reduce the time your query takes

User · Answer

For the first question  why not just use   SELECT COUNT    FROM myTable    to get the count   And for the second question  the primary key of the row is what should be used to identify a particular row   Don t try and use the row number for that     If you returned Row Number   in your main query   SELECT ROW NUMBER   OVER  Order by Id  AS RowNumber  Field1  Field2  Field3 FROM User   Then when you want to go 5 rows back then you can take the current row number and use the following query to determine the row with currentrow -5  SELECT us Id FROM  SELECT ROW NUMBER   OVER  ORDER BY id  AS Row  Id      FROM User   us  WHERE Row   CurrentRow - 5

User · Answer

If you absolutely want to use ROW NUMBER for this  instead of count     you can always use   SELECT TOP 1 ROW NUMBER   OVER  ORDER BY Id     FROM USERS   ORDER BY ROW NUMBER   OVER  ORDER BY Id  DESC

User · Answer

SQL Row Number   function is to sort and assign an order number to data rows in related record set  So it is used to number rows  for example to identify the top 10 rows which have the highest order amount or identify the order of each customer which is the highest amount  etc   If you want to sort the dataset and number each row by seperating them into categories we use Row Number   with Partition By clause  For example  sorting orders of each customer within itself where the dataset contains all orders  etc   SELECT     SalesOrderNumber      CustomerId      SubTotal      ROW NUMBER   OVER  PARTITION BY CustomerId ORDER BY SubTotal DESC  rn FROM Sales SalesOrderHeader   But as I understand you want to calculate the number of rows of grouped by a column  To visualize the requirement  if you want to see the count of all orders of the related customer as a seperate column besides order info  you can use COUNT   aggregation function with Partition By clause  For example   SELECT     SalesOrderNumber      CustomerId      COUNT    OVER  PARTITION BY CustomerId  CustomerOrderCount FROM Sales SalesOrderHeader

User · Answer

SELECT num  UserName FROM    SELECT UserName  ROW NUMBER   OVER ORDER BY UserId  AS num   From Users  AS numbered WHERE UserName  Joe

User · Answer

Need to create virtual table by using WITH table AS  which is mention in given Query   By using this virtual table  you can perform CRUD operation w r t row number   QUERY   WITH table AS -  SELECT row number   OVER ORDER BY UserId  rn    FROM Users  - SELECT   FROM table WHERE UserName  Joe  -   You can use INSERT  UPDATE or DELETE in last sentence by in spite of SELECT

User · Answer

May not be related to the question here  But I found it could be useful when using ROW NUMBER -   SELECT    ROW NUMBER   OVER  ORDER BY  SELECT 100   AS Any ID  FROM  Any Table

User · Answer

This query   SELECT ROW NUMBER   OVER ORDER BY UserId  From Users WHERE UserName  Joe    will return all rows where the UserName is  Joe  UNLESS you have no UserName  Joe   They will be listed in order of UserID and the row number field will start with 1 and increment however many rows contain UserName  Joe   If it does not work for you then your WHERE command has an issue OR there is no UserID in the table  Check spelling for both fields UserID and UserName

User · Answer

You can use Row Number for limit query result   Example   SELECT   FROM       select row number   OVER  order by createtime desc  AS ROWINDEX        from TABLENAME   TB WHERE TB ROWINDEX between 0 and 10   -- With above query  I will get PAGE 1 of results from TABLENAME

User · Answer

ROW NUMBER   returns a unique number for each row starting with 1  You can easily use this by simply writing  ROW NUMBER   OVER  ORDER BY  Column Name  DESC  as ROW NUMBER

User · Answer

You can use this for get first record where has clause  SELECT TOP 1      ROW NUMBER   OVER ORDER BY UserId  AS rownum  FROM     Users  WHERE    UserName    Joe  ORDER BY rownum ASC

User · Answer

select    Ml Hid    ml blockid    row number   over  partition by ml blockid order by Ml Hid desc  as rownumber    H HNAME  from MIT LeadBechmarkHamletwise ML join  MT HAMLE  h on ML Hid h HID

[sql] How do I use ROW_NUMBER()?

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