MySQL的：SUM 2页联合在一起的表（4×SUM在一个结果）

Question

我必须进行选择，被联合在一个简单的查询...

 
SELECT description_x, a, b, c, d from table a WHERE person_id = 1 
UNION 
SELECT description_y, e ,f ,g ,h from table b WHERE person_id = 1 

... A，B，C，d，E，F ，g，h都是整数。我怎样才能他们，结果会看起来像这样...

 
row 1: description_x | a | b | c | d 
row 2: description_y | e | f | g | h 
row 3: summary  | a+e | b+f | c+g | d+h 

...好吗？

非常感谢！

Answer 1

您可以添加另一个union它将做聚合。

select description_x, a, b, c, d from table a where person_id = 1 
union all 
select description_y, e ,f ,g ,h from table b where person_id = 1 
union all 
select 'summary', sum(a), sum(b), sum(c), sum(d) from (
    select a, b, c, d from table a where person_id = 1 
    union all 
    select e ,f ,g ,h from table b where person_id = 1 
) t 

我们将不需要再次重写相同的查询如果MySQL支持的热膨胀系数（正如在评论中提到的，是在MySQL 8日起推出）。

Answer 2

select sum(a) as a,sum(b) as b,sum(c) as c,sum(d) as d from (
SELECT description_x, a, b, c, d from table a WHERE person_id = 1 
UNION All 
SELECT description_y, e ,f ,g ,h from table b WHERE person_id = 1 
)T