在MySQL中汇总UNION结果的一种简单方法 [英] a simple way to sum a result from UNION in MySql

问题描述

我有三个表(t1，t2，t3)的并集. 每个重新运行的记录数完全相同，第一列是id，第二个量是:

I have a union of three tables (t1,t2,t3). Each rerun exactly the same number of records, first column is id, second amount:

1  10
2  20
3  20

1  30
2  30
3  10

1  20
2  40
3  50

是否有简单的sql方式将其总结为:

Is there a simple in sql way to sum it up to only get:

1   60
2   80
3   80

推荐答案

select id, sum(amount) from (
    select id,amount from table_1 union all
    select id,amount from table_2 union all
    select id,amount from table_3
) x group by id

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