要求更新 T2中的LH_CODE

UPDATE T1,T2
SET T2.LH_CODE = T1.LH_CODE
WHERE
T2.CX_CODE = T1.CX_CODE

UPDATE T2
SET LH_CODE = (
SELECT
T1.LH_CODE
FROM
T1
WHERE
T1.CX_CODE = CX_CODE
);
我这样写报错为返回多个值

没有看懂啥意思？逻辑是什么、