sum不能用到两个表中吗？

白日梦游

合计出的数据不对
SELECT SUM(a.a) AS AA, SUM(b.b) AS BB
FROM a,b

unkmass

SELECT SUM(a.a) AS AA, SUM(b.b) AS BB
FROM a,b
===============
你这是计算的笛卡尔积,当然不对了,应该加上关联条件,即:
SELECT SUM(a.a) AS AA, SUM(b.b) AS BB
FROM a,b
where a.主键=b.主键

johnseven

yes

我是杀人狂

ls正解..

wgfxman

如果真想笛卡尔乘，where 1=1也可以

fanfan1980

--try

select
AA=(select sum(a) from a),
BB=(select sum(b) from b)