How to use a mysql stored procedure

A stored procedure is a procedure (like a subprogram in a regular computing language) that is stored (in the database). Correctly speaking, MySQL supports "routines" and there are two kinds of routines: stored procedures which you call, or functions whose return values you use in other SQL statements the same way that you use pre-installed MySQL functions like pi(). I'll use the word "stored procedures" more frequently than "routines" because it's what we've used in the past, and what people expect us to use.

A stored procedure has a name, a parameter list, and an SQL statement, which can contain many more SQL statements. There is new syntax for local variables, error handling, loop control, and IF conditions. Here is an example of a statement that creates a stored procedure.

CREATE PROCEDURE procedure1 /* name */
(IN parameter1 INTEGER) /* parameters */
BEGIN /* start of block */
DECLARE variable1 CHAR(10); /* variables */
IF parameter1 = 17 THEN /* start of IF */
SET variable1 = 'birds'; /* assignment */
ELSE
SET variable1 = 'beasts'; /* assignment */
END IF; /* end of IF */
INSERT INTO table1 VALUES (variable1); /* statement */
END /* end of block */

What I'm going to do is explain in detail all the things you can do with stored procedures. We'll also get into another new database object, triggers, because there is a tendency to associate triggers with stored procedures.