CREATE TABLE t1(a int) engine=innodb;
INSERT INTO t1 VALUES (1);
SELECT DISTINCT
convert((SELECT des_decrypt(2,1) AS a FROM t1 WHERE @a:=1), signed) as d
FROM t1 ;
d
2
Warnings:
Warning	1287	'DES_DECRYPT' is deprecated and will be removed in a future release. Please use AES_DECRYPT instead
DROP TABLE t1;