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DECLARE @.Temp int
DECLARE @.FullQry varchar(50)

set @.FullQry='select @.Temp=Emp_ID from Employee where....'
Exec(@.FullQry)
select @.@.ROWCOUNT

My Employee table has 3 records and this query sholud return me @.@.ROWCOUNT=1
but it will return 0 why this i am not able to find out.Exec function return ROWCOUNT or not?The domain of the selection "@.Temp=" is outside the domain of the executed statement so the query as you have written it will return:

Server: Msg 137, Level 15, State 1, Line 1
Must declare the variable '@.Temp'.

(1 row(s) affected)

The correct way to return values from a dynamically executed SQL section is to use sp_executesql with output semantics:

DECLARE @.Temp int
DECLARE @.Rows int
DECLARE @.sql nvarchar(4000)

SET @.sql=N'SELECT @.Rows=@.@.ROWCOUNT, @.Temp=EMp_ID FROM ...'

EXEC sp_executesql @.sql, N'@.Temp int OUTPUT, @.Rows int OUTPUT', @.Temp OUTPUT, @.Rows OUTPUT

SELECT @.Rows, @.Temp