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添加多个SQL选择的结果?

join mysql sql

1

Daniel Bingham · 技术社区 · 15 年前

select sum(field_one) from t_a join t_b on (t_a.bid = t_b.id) where t_b.user_id=:id
select sum(field_two) from t_c join t_d on (t_c.did = t_d.id) where t_d.user_id=:id
select sum(field_three) from t_e where t_e.user_id=:id

我需要的是这三个值的总和。 sum(field_one)+sum(field_two)+sum(field_three)

3 回复 | 直到 15 年前

1

8

Peter Lang 15 年前

你可以的 UNION ALL 他们。
不要使用 UNION 5+5+5 会导致 5

Select Sum(s)
From
(
  Select Sum(field_one) As s ...
  Union All
  Select Sum(field_two) ...
  Union All
  Select Sum(field_three) ...
) x

2

5

Thakur 15 年前

你不需要像这样使用并集就可以做到这一点

示例查询

select( (select 15) + (select 10) + (select 20))

你的问题

select
(
    (select sum(field_one) from t_a join t_b on (t_a.bid = t_b.id) where t_b.user_id=:id) +
    (select sum(field_two) from t_c join t_d on (t_c.did = t_d.id) where t_d.user_id=:id) +
    (select sum(field_three) from t_e where t_e.user_id=:id) 
)

3

Dennis Haarbrink 15 年前

UNION 再选择一个子选项:

select sum(`sum`) FROM
(
  select sum(field_one) as `sum` from t_a join t_b on (t_a.bid = t_b.id) where t_b.user_id=:id
  UNION ALL
  select sum(field_two) from t_c join t_d on (t_c.did = t_d.id) where t_d.user_id=:id
  UNION ALL
  select sum(field_three) from t_e where t_e.user_id=:id
) as x;

编辑:根据peterlang的建议,更新了我的答案使用unionall。