Running a MySQL Procedure with OUT parameters

OUT parameters for MySQL procedures are returned in pseudo variables. To view the value of these variables, you must run a query to return these values.

Example:

call film_in_stock(1,2,@p_film_count);

select @p_film_count;

Here:

the call statement runs the procedure, passing values for the first two parameters
the third parameter is in OUT parameter. A pseudo variable is specified here to receive the value
the select statement will display the value of the return pseudo variable

AQT will handle this situation automatically by using SQL similar to the above.

Advanced Query Tool

https://www.querytool.com