Question

I wrote a stored procedure which returns contract status for anauthor. If author doesn’t exist i’ll return -900. So, this is what i did

  CREATE PROCEDURE AUthorContract
    @user varchar(10)
       AS
          IF(@user NOT IN(select Au_id from Authors))
           BEGIn
               RETURN -900
          END
      ELSE
       BEGIN
         select contract from from Authors where Au_id = @user
       END

       GO

However, when I give a valid author id as input, it returns -900 and if i give some id it goes into else and just returns 0 . So, I reversed them and entered correct id, but it still just returns 0 and not the contract value.
Can u please help me out the mistake i have been doing. The DB is pubs.

Answer 1

stored procedure can “return” three types of things:

• int return value, via RETURN command
• output parameter value, via parameter list: @YourPartameter anydatatype OUTPUT
• result set: SELECT * FROM YourTable

your procedure does not have a RETURN command for normal exit, so it defaults to a value of zero. You need to check the result set in your application if the return value is zero.

try this to RETURN the contact value:

CREATE PROCEDURE AUthorContract
    @user varchar(10)
       AS
       DECLARE @contract int
          IF(@user NOT IN(select Au_id from Authors))
           BEGIn
               RETURN -900
          END
      ELSE
       BEGIN
         select @contract=contract from from Authors where Au_id = @user
       END

       RETURN @contract

       GO

try this to use an OUTPUT parameter:

CREATE PROCEDURE AUthorContract
    @user varchar(10), @contract varchar(30) OUTPUT
       AS
          IF(@user NOT IN(select Au_id from Authors))
           BEGIn
               RETURN -900
          END
      ELSE
       BEGIN
         select @contract=contract from from Authors where Au_id = @user
       END

       RETURN 0

       GO

Here is the result set, with an explicit return:

CREATE PROCEDURE AUthorContract
    @user varchar(10)
       AS
          IF(@user NOT IN(select Au_id from Authors))
           BEGIn
               RETURN -900
          END
      ELSE
       BEGIN
         select contract from from Authors where Au_id = @user
       END

       RETURN 0

       GO