sql - 将两个匿名表相互连接

Question

以下查询运行:

select foo.g from (select 'hello' as g) as foo

并且此查询也会运行:

select bla.x from (select 'world' as x) as bla

但这个不是:

select * from (select foo.g from (select 'hello' as g) as foo) join (select bla.x from (select 'world' as x) as bla)

我收到以下错误消息:

Msg 156, Level 15, State 1, Line 1
Incorrect syntax near the keyword 'join'.

为什么会报错？是否有可能以某种方式连接这些表？

Answer 1

使用 As <temp_table_name> 给你的表命名并且您需要指定列 两个表正在连接 ON .由于没有栏目加入ON我使用了重言式(结果总是True)假设你期望的结果是:你好，世界在两列

这是重新排列的查询:

select * 
from 
(
    select foo.g 
    from 
    (
        select 'hello' as g
    ) as foo
) As t1
inner join 
(
    select bla.x 
    from (select 'world' as x) as bla
) As t2 ON 1 = 1