Exiting a MySQL Stored Procedure in the middle of the code
While exiting a MySQL function is fairly straight-forward, simply use the RETURN keyword, exiting a Stored Procedure is not quite as obvious. There is no EXIT keyword, however you can use the LEAVE keyword and specify a label that is associated with the BEGIN of the Stored Procedure. In this way, you are defining the Stored Procedure with a Label, which the LEAVE statement can then act upon.
As an example, look at the following Stored Procedure :
CREATE PROCEDURE TestProc(Value INT)
ThisSP:BEGIN
IF Value is null or Value=0 then
Select ‘Invalid Value’;
LEAVE ThisSP;
END IF;
Select * from Table twhere t.Value=Value;
END;