获取4个不同表的总SUM结果

Question

我有4个具有相同列的表（id＆amp; banka_id＆amp; miktar）。

2个表格收入（drink_earn，eat_earn）和

2桌消费（drink_spending，eat_spending）

|id|banka_id|miktar|
---|--------|------|
|1 |2       |20    |
|2 |1       |20    |
|3 |1       |30    |

我的问题。

如何计算行中的所有内容？

drink_earn：表SUM（miktar）= 50 $

eat_earn：表SUM（miktar）= 50 $

drink_spending：表SUM（miktar）= 15 $

eat_spending：表SUM（miktar）= 5 $

收入：drink_earn + eat_earn = 100 $

支出：drink_spending + eat_spending 20 $

总计：收入 - 消费= 80美元

最后是GROUP BY banka_id

你能写代码样本吗？问候。

Answer 1

使用UNION ALL将所有表合并为一个：

select banka_id, sum(earn) - sum(spend) as total
from (
    select banka_id, miktar as earn, 0 as spend
    from drink_earn
    union all
    select banka_id, miktar as earn, 0 as spend
    from eat_earn
    union all
    select banka_id, 0 as earn, miktar as spend
    from drink_spending
    union all
    select banka_id, 0 as earn, miktar as spend
    from eat_spending
) t
group by banka_id

但如果你只有一个表中的所有数据以及一个额外的类型列，那就更好了。