什么是此查询的正确解决方案

Question

您的SQL语法有误；检查与您的MariaDB服务器版本相对应的手册以获取正确的语法，以在'alias1）联接附近使用（在第1行的*从（route b join stop stopb on b.stop = stopb.id）中选择*作为a

select * 
from 
  (select * from (route a join stops stopa on a.stop=stopa.id) as alias1)
join 
  (select * from (route b join stops stopb  on b.stop=stopb.id) as alias 2)
on alias1.num=alias2.num and alias1.company=alias2.company

Answer 1

您需要为子查询添加别名：

select * 
from 
  (select * from route a join stops stopa on a.stop=stopa.id) as alias1
join 
  (select * from route b join stops stopb on b.stop=stopb.id) as alias2
on alias1.num=alias2.num and alias1.company=alias2.company