set sql_mode='STRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION';
use test;
drop table gafld;
CREATE TABLE gafld (
  nuigafld integer NOT NULL,
  ucrgafld varchar(30) COLLATE utf8_bin NOT NULL DEFAULT substring_index(user(),'@',1)
);
explain UPDATE gafld
SET nuigafld = 0
WHERE nuigafld = 10 ;
explain UPDATE gafld
SET nuigafld = 0
WHERE nuigafld = 10 ;