mysql更新數據，條件為實時查詢出來的數據

--將更新條件保存到臨時表里
CREATE TABLE tmp3 AS (SELECT  username FROM oa_user  WHERE username NOT IN (SELECT  username FROM nst_t_account));
--更新表數據，條件從臨時表里取
UPDATE oa_user SET usr_update=NOW() WHERE username IN (SELECT username FROM tmp3);
--刪除臨時表
DROP TABLE tmp3;