Question

I’m wondering why I can’t use a CAST function as the parameter to SET ROWCOUNT in a Stored Procedure.

This code fails:

CREATE PROCEDURE GetTransactions
    @Count VARCHAR(5)
AS

    SET ROWCOUNT CAST(@Count AS INT);
...

While this code with an intermediary variable works:

CREATE PROCEDURE GetTransactions
    @Count VARCHAR(5)
AS
    Declare @Rows AS INT;
    SET @Rows = CAST(@Count AS INT);

    SET ROWCOUNT @Rows;
...

I know that changing the parameter type to INT would also fix this, but the middle-tier component that calls the Stored Procedure needs everything to be a String type.

Answer 1

As in many cases with SQL Server’s TSQL implementation, you cannot pass an expression to SET ROWCOUNT. The valid arguments to SET ROWCOUNT are either a number (constant) or a simple variable:

SET ROWCOUNT { number | @number_var } 

number | @number_var

Is the number, an integer, of rows to be processed before stopping the specific query.

The same applies to calling a stored procedure, in that you can’t have expressions as parameters.