Question

我尝试使用ansi连接将两个表连接到一个表。我可以在哪里

这样做

加入地点：

select
   name.name,
   middle.name,
   last.name
from
   name,
   middle,
   last
where
   name.middleid = middle.id
   and name.lastid = last.id
   and name.name = 'BOB'

我能够弄清楚如何将中间名称加入名称表，但是一旦我在最后一张表中添加，我就不成功

ANSI JOIN: 
    select
       name.name,
       middle.name,
       last.name
    from
       name join middle on name.middleid = middle.id
       **-- How do i join the name table to the last table?**
    where
    name.name = 'BOB'

Answer 1

试

ANSI JOIN: 
    select
       name.name,
       middle.name,
       last.name
    from
       name join middle on name.middleid = middle.id
       join last on name.lastid = last.id
       **-- How do i join the name table to the last table?**
    where
    name.name = 'BOB'

Answer 2

它在你的问题中

select
   name.name,
   middle.name,
   last.name
from
   name join middle on name.middleid = middle.id
   join last on name.lastid = last.id 
where
name.name = 'BOB'

Answer 3

一旦你加入了两个表，就把它们想象成一个不方便用不同的表（也就是命名空间）为列名加前缀的

所以你再次加入两张桌子。

Answer 4

ANSI JOIN：

   select
       name.name,
       middle.name,
       last.name
    from
       name 
       join middle on name.middleid = middle.id
       join last on name.lastid = last.id      
    where
    name.name = 'BOB'

Ansi将两个表连接到一个表

4 个答案: