functions for converting a UUID stored as VARBINARY(16) into its UUID form and vice versa

mysql-convert-varbinary-to-uuid.sql

/*
* From here:  http://mysql.rjweb.org/doc.php/uuid
*/
-- Convert a formatted UUID to a BINARY(16)
CREATE FUNCTION UuidToBin(_uuid CHAR(36))
    RETURNS BINARY(16)
    LANGUAGE SQL  DETERMINISTIC  CONTAINS SQL  SQL SECURITY INVOKER
RETURN
    UNHEX(CONCAT(
        SUBSTR(_uuid, 15, 4),
        SUBSTR(_uuid, 10, 4),
        SUBSTR(_uuid,  1, 8),
        SUBSTR(_uuid, 20, 4),
        SUBSTR(_uuid, 25) ));

-- Convert a VARBINARY(16) to a formatted UUID
CREATE FUNCTION UuidFromBin(_bin BINARY(16))
        RETURNS CHAR(36)
        LANGUAGE SQL  DETERMINISTIC  CONTAINS SQL  SQL SECURITY INVOKER
    RETURN
		LCASE(CONCAT_WS('-', HEX(SUBSTR(_bin, 1, 4)),
		HEX(SUBSTR(_bin, 5, 2)),
		HEX(SUBSTR(_bin, 7, 2)),
		HEX(SUBSTR(_bin, 9, 2)),
		HEX(SUBSTR(_bin, 11))));