a MySQL user defined function that takes in a number and uses it to generate a guid

UUID.sql

# a MySQL user defined function that takes in a number and uses it to generate a guid

CREATE FUNCTION generateGuid(num INT) RETURNS CHAR(32)
BEGIN
 DECLARE guid CHAR(32);
 SET guid = CONCAT(
   SUBSTR(SHA1(RAND()), 1, 8), '-',
   SUBSTR(SHA1(RAND()), 1, 4), '-',
   SUBSTR(SHA1(RAND()), 1, 4), '-',
   SUBSTR(SHA1(RAND()), 1, 4), '-',
   IF(LENGTH(num)>12, SUBSTR(SHA1(RAND()), 1, 12), CONCAT(REPEAT('0', 12-LENGTH(num)),num ) )
 );
 RETURN guid;  
END;