Mysql - Stored procedure OUT variable return null

Question

My Table Structure is:

DROP TABLE IF EXISTS `child`;

CREATE TABLE `child` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) NOT NULL,
  PRIMARY KE         


        

Answer 1

The syntax for setting the variable is incorrect, use : like,

SET parent_id := LAST_INSERT_ID();
 SET child_id := LAST_INSERT_ID();

or You can do the setting as

select LAST_INSERT_ID() into parent_id;

Answer 2

You might have already solved this by now, but the first thing I noticed about your stored procedure is that you have a local variable with the same name as the output variable (parent_id). It looks to me that you're setting the value of the local variable rather than the return variable, so the caller never sees the correct value.

Perhaps removing the local parent_id variable declaration will solve your problem.