How Can i Let Stored Procedure Returns Varchar Value? - sql

Question

Here is my sample:
ALTER PROCEDURE EmpFirstName
#myParam int,
#empFName varchar(20) output
AS
BEGIN
SET NOCOUNT ON;
SELECT #empFName = empfname
FROM FE_QEMP
WHERE empno = #myParam
END
GO
myParam is the input and empFName will carry the output, so the procedure
should only take 1 parameter since empFName is the output, but in my case
i get this error:
Msg 201, Level 16, State 4, Procedure
EmpFirstName, Line 0 Procedure or
function 'EmpFirstName' expects
parameter '#empFName', which was not
supplied.
This is the way i called the procedure:
DECLARE #returnValue varchar(20)
EXEC #returnValue = EmpFirstName 10
SELECT 'Return Value ' = #returnValue

Answer 1

Return values and output parameters are two different things. If you want to call it with an output parameter, you'd do it like this:
EXEC EmpFirstName 10, #returnValue OUTPUT
SELECT 'Return Value ' + #returnValue
If you want to call it in the manner that you described in your example, then you need to alter the stored procedure to state RETURNS VARCHAR(20) and remove the output parameter. To return a value, you have to explicitly call return. In your example, you'd declare a variable, assign it in the select statement, then call return #varName.

Answer 2

Thanks. My aha moment came with this post. Did not realise that output parameters need to be qualified with the "output" identifier too when executed, not just in the procedure!
Here are my test workings for my fellow sql server noobs. I am using sqlcmd with sql server 2005.
The stored procedure:
/* :r procTest.sql */
if exists (select name from sysobjects where name="procTest" and type="P")
drop procedure procTest;
go
create procedure procTest
/* Test stored procedure elements. */
(#i_pt_varchar varchar(20),
#o_pt_varchar varchar(20) output)
as
begin
print "procTest";
set #o_pt_varchar = "string coming out";
print "#i_pt_varchar " + #i_pt_varchar;
print "#o_pt_varchar " + #o_pt_varchar;
return (0);
end
go
The test call:
/* :r procTest.test.sql */
declare #returnFlag int;
declare #i_varchar varchar(20);
declare #o_varchar varchar(20);
set #i_varchar = "string going in";
set #o_varchar = null;
execute #returnFlag = procTest #i_varchar, #o_varchar output
print "#returnFlag " + cast(#returnFlag as varchar(20));
print "after call";
print "#i_varchar " + #i_varchar;
print "#o_varchar " + #o_varchar;
go