How to define custom STATIC Global Variables/Constants in MySQL
Since MySQL 5.5 it's not possible to set a global user-defined variable.

A work-around might be to create a stored procedure that would return what you need.

DROP PROCEDURE IF EXISTS HOUSE_SMALL_TYPE;
DELIMITER //
CREATE PROCEDURE HOUSE_SMALL_TYPE ()
BEGIN 
SELECT 0;
END//
DELIMITER ;


and then call it.

CALL HOUSE_SMALL_TYPE();
The DROP statement is required in order to be able to modify it.

Credit to shock_one on SO for the above answer

I was also thinking another option may be setting your constant values in a seperate table that all of your stored procedures could access.