请问在SQL查询中,如何在结果里增加1列,该列是每行值的总合?

Question

比如:select * from aaa ??? 如何生成下面结果
a1 a2 a3 总合(该字段利用查询自动生成)
1 2 3
2 2 4

Answer 1

首先要确认a1,a2两列都是数值类型或者可以隐式转换为数值类型，如果可以的话可以用下面的语句实现：
select a1,a2,(a1+a2) as a3 from aaa.

Answer 2

select a1,a2,a3,a1+a2+a3 as 总和
from aaa
就OK

Answer 3

select a1,a2,a3 as a1+a2 from aaa
要么就是select a1,a2,a3=a1+a2 from aaa

Answer 4

select a.a1,a.a2,a.a3,(a.a1+a.a2+a.a3) 总合 from aaa;