Syntax:
SHOW {PROCEDURE | FUNCTION} CODE sp_name

These statements are MySQL extensions that are available only for
servers that have been built with debugging support. They display a
representation of the internal implementation of the named routine. The
statements require that you be the owner of the routine or have SELECT
access to the mysql.proc table.

If the named routine is available, each statement produces a result
set. Each row in the result set corresponds to one "instruction" in the
routine. The first column is Pos, which is an ordinal number beginning
with 0. The second column is Instruction, which contains an SQL
statement (usually changed from the original source), or a directive
which has meaning only to the stored-routine handler.

URL: http://dev.mysql.com/doc/refman/5.0/en/show-procedure-code.html

