请教一个Sql问题

苏宁No.1

请问T-SQL对于嵌套是如何处理的？即类似于
Select * from (select * from)

我要从一个select结果集里进行一些column的sum，不如如何写SQL

nanswn

select column [具体的列名]
from  [表名]
where [条件]

chenjing957

table：tb
A   B     C
1 100 100
2 200 200
2 300 300

select sum(B) sum_B,sum(C) sum_C
from
(select B,C from tb where A = 2)

result：
sum_B sum_C
500      500

lucky7_2000

Select * from (select * from)
把括号中的语句结果当作一个表就可以了.

ivorn.zhang

Select a, sum(b) as sum_b, sum(c) as sum_c
From (Select a, b, c
          From table_A) table_B
Group by a

sqysl

楼上两位的写法，不如不用括号里的集合表，干脆写表名多好啊？
Select a, sum(b) as sum_b, sum(c) as sum_c
From (Select a, b, c
          From table_A) table_B
Group by a
----》
Select a, sum(b) as sum_b, sum(c) as sum_c
From  table_A
Group by a