Not allowed to return a result set from a function.

Hi Experts,

 Can anyone tell me why I keep getting the following  error, when my goalis to return a single value?

error 1415 (0A000): Not allowed to return a result set from a function.

My code
 DELIMITER $$

 CREATE FUNCTION get_author_cost(auth_id SMALLINT(5)) RETURNS DECIMAL(10,2)

 BEGIN

 DECLARE dTotal DECIMAL(10,2);

 SELECT @dTotal:=SUM(price) 
 FROM books
 WHERE author = auth_id;

 RETURN dTotal;

 END $$


 DELIMITER ;

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APD TorontoAsked:
Who is Participating?
 
Guy Hengel [angelIII / a3]Connect With a Mentor Billing EngineerCommented:
actually, I would suggest to do the other way round, and not use @, as it's for session-level variables ...
DELIMITER $$

 CREATE FUNCTION get_author_cost(auth_id SMALLINT(5)) RETURNS DECIMAL(10,2)

 BEGIN

 DECLARE dTotal DECIMAL(10,2);

 SELECT SUM(price)  
     INTO dTotal
 FROM books
 WHERE author = auth_id;

 RETURN dTotal;

 END $$
 DELIMITER ;

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0
 
Jim P.Commented:
Try changing dTotal to @dTotal.
0
 
Vadim RappConnect With a Mentor Commented:
In the function, you can use syntax select column into variable, but not select variable:=column. Even though the result is the same, mysql expects select with into. From documentation:

http://dev.mysql.com/doc/refman/5.0/en/create-procedure.html

Statements that return a result set can be used within a stored procedure but not within a stored function. This prohibition includes SELECT statements that do not have an INTO var_list clause and other statements such as SHOW, EXPLAIN, and CHECK TABLE

So, when it encounters select without into, it generates an error.
0
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