MySQL: convert BINARY(16) to GUID (UUID)

uuid_from_bin.sql

# MySQL: convert BINARY(16) to GUID (Microsoft-style UUID)
# 0x11223344556677889900AABBCCDDEEFF → '44332211-6655-8877-9900-AABBCCDDEEFF'
# Usage: CREATE TABLE example (id INT NOT NULL PRIMARY KEY AUTO_INCREMENT, guid BINARY(16) NOT NULL UNIQUE);
#        SELECT id, uuid_from_bin(guid) FROM example;
# Tested on: MySQL 5.6, 5.7, 8.0

CREATE FUNCTION uuid_from_bin(b BINARY(16))
  RETURNS char(36) CHARSET utf8
  DETERMINISTIC
BEGIN
  DECLARE h CHAR(32);
  SET h=HEX(b);
  RETURN CONCAT(SUBSTRING(h,7,2), SUBSTRING(h,5,2), SUBSTRING(h,3,2), SUBSTRING(h,1,2),
    '-', SUBSTRING(h,11,2), SUBSTRING(h,9,2),
    '-', SUBSTRING(h,15,2), SUBSTRING(h,13,2),
    '-', SUBSTRING(h,17,4),
    '-', SUBSTRING(h,21,12));
END

error with maria 10.2.12