Question

Table A1                            Table B1

A --100 id =1                      A --100 id=1

B -- 100 id =2                     A -100  id=1

C -- 200 id=3                      A - 100 id =1

需要对两个表中的所有值求和，其中id = 1。

select (SUM(A1.A) + SUM(nvl(B1.A,0))) SUM from A1 a, B1 b where a.id='1' AND b.id='1';

我得到的金额为600，但应该是400

Answer 1

这样的事情应该有效。

SELECT id, SUM(A) as Totals FROM
(
 SELECT id, A FROM A1
 UNION ALL
 SELECT id, A FROM B1
) AS tblData
GROUP BY id

Answer 2

您使用了CROSS JOIN（笛卡尔积），因此您获得了600 ..

您可以尝试使用UNION结合两个表格。

SELECT SUM(T.Totle)
FROM 
(
    select SUM(A1.A) Totle from A1 a where a.id='1'
    UNION ALL
    select SUM(B1.A) Totle from B1 b where b.id='1'
) T

SQLFiddle

Answer 3

您可以使用：

SELECT COALESCE((SELECT SUM(A) FROM A1 WHERE ID = 1), 0) +
       COALESCE((SELECT SUM(A) FROM B1 WHERE ID = 1), 0)

Answer 4

你可以这样做

    select sum(A) as total
    from
    (
        select A 
        from A1 where id = 1                           
        union all
        select A 
        from B1 where id = 1
    ) t

Answer 5

这是一个不使用子查询的方法（虽然我不推荐它）：

select coalesce(sum(a.a), 0) + coalesce(sum(b.b), 0)
from a full outer join
     b
     on 1 = 0 
where a.id = 1 or b.id = 1;

从两个表中的不同列添加多个值

5 个答案: