Stored procedures can access and set local, session, and global variables.
Local variables are either passed in as parameters or created using the DECLARE statement.
Using the DECLARE statement with a DEFAULT will set the value of a local variable:
DECLARE myInt INT DEFAULT 0;
You can assign values to local, session, and global variables using the SET statement:
SET myInt = 5;
MySQL's SET statement permits setting multiple variables in one statement:
SET myInt1 = 5, myInt2 = 50;