mysql - 如何加入自己的选择？

Question

1. 连接一个表和它本身是没有问题的。但我需要加入一个创建的选择本身。第一个想法:使用临时表，但我只能打开它一次。这是真的吗？

2. MySQL 是否足够聪明，可以计算一个始终具有相同术语的子查询只计算一次？例如:

   join (select * from asdf where term) as one
   join (select * from asdf where term) as two
   ...
   join (select * from asdf where term) as ten
   

一般是怎么解决的？

Answer 1

你可以多次加入临时表

    select * into #temp from asdf where term
    ...
    join #temp as one
    join #temp as two
    ...
    join #temp as ten