To SELECT only top N rows from a table we can use TOP clause in SELECT statement. Using TOP clause we can also specify percentage option.
For example, both of these statements are valid:
USE SqlAndMe
GO
SELECT TOP 5 EmployeeId,FirstName,LastName
FROM dbo.Table_Employees
GO
SELECT TOP 5 PERCENT EmployeeId,FirstName,LastName
FROM dbo.Table_Employees
GO
EmployeeId FirstName LastName
1 Ken Sánchez
2 Terri Duffy
3 Gail Erickson
4 Ken Sánchez
5 Terri Duffy
(5 row(s) affected)
EmployeeId FirstName LastName
1 Ken Sánchez
(1 row(s) affected)
Another way to limit rows in result set is to use SET ROWCOUNT N statement. SET ROWCOUNT N stops processing the query after specified number of rows are returned.
It can be used as below:
USE SqlAndMe
GO
SET ROWCOUNT 5
GO
SELECT EmployeeId,FirstName,LastName
FROM dbo.Table_Employees
GO
SET ROWCOUNT 1
GO
SELECT EmployeeId,FirstName,LastName
FROM dbo.Table_Employees
GO
EmployeeId FirstName LastName
1 Ken Sánchez
2 Terri Duffy
3 Gail Erickson
4 Ken Sánchez
5 Terri Duffy
(5 row(s) affected)
EmployeeId FirstName LastName
1 Ken Sánchez
(1 row(s) affected)
Using SET ROWCOUNT N affects current session, to turn off this setting we need to set it to 0.
SET ROWCOUNT 0
GO
There are some differences between using SET ROWCOUNT N and TOP N [PERCENT]. You can read about these differences here: SET ROWCOUNT VS TOP in SQL Server
Hope This Helps!
Vishal
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Filed under: SQLServer, SQLServer 2005, SQLServer 2008, SQLServer 2008 R2, SQLServer 2012, Working With Data
