Thursday, April 2, 2015

SET ROWCOUNT - SQL Server to stop processing the query after the specified number of rows are returned


NOTE:Setting the SET ROWCOUNT option causes most Transact-SQL statements to stop processing when they have been affected by the specified number of rows. This includes triggers. The ROWCOUNT option does not affect dynamic cursors, but it does limit the rowset of keyset and insensitive cursors. This option should be used with caution.
SET ROWCOUNT overrides the SELECT statement TOP keyword if the rowcount is the smaller value.
The setting of SET ROWCOUNT is set at execute or run time and not at parse time.

SET ROWCOUNT stops processing after the specified number of rows. In the following example, note that over 500 rows meet the criteria of Quantity less than 300. However, after applying SET ROWCOUNT, you can see that not all rows were returned.
USE AdventureWorks2012;
GO
SELECT count(*) AS Count
FROM Production.ProductInventory
WHERE Quantity < 300;
GO
Here is the result set.
Count
-----------
537
(1 row(s) affected)
Now, set ROWCOUNT to 4 and return all rows to demonstrate that only 4 rows are returned.
SET ROWCOUNT 4;
SELECT *
FROM Production.ProductInventory
WHERE Quantity < 300;
GO
(4 row(s) affected)

No comments:

Post a Comment