我可以做这个:
SELECT t2.value + sum(t3.value)
FROM tableA t2, tableB t3
WHERE t2.somekey = t3.somekey
GROUP BY t3.somekey
但是如何做到这一点?
UPDATE tableA t1
SET speed = (
SELECT t2.value + sum(t3.value)
FROM tableA t2, tableB t3
WHERE t2.somekey = t3.somekey
AND t1.somekey = t3.somekey
GROUP BY t3.somekey
)
;
MySQL 说这是非法的,因为您不能t1
在 FROM 子句中指定要更新的目标表。