Question

单个字段求和并和其他表字段相加，SQL语句怎么写

Answer 1

这样写
select a.需要相加的字段+b.求和 from 表A a
join (select 关联所需要的列,sum(求和列) as 求和 from 表B) b
on a.列名=b.关联所需要的列
如果是你需要的A表整体求和，和B表的某字段相加 则写：
select a.需要相加的字段+b.求和 from 表A a
join (select sum(求和列) as 求和 from 表B) b
on 1=1

Answer 2

select sum(a.col1)+sum(b.col1)
from a
left jon b
on a.col=b.col