mysql join总结

 

内连接：[inner|cross] join （不带inner或cross时也值内连接）

 

外连接:

               左外连接：left [outer] join

               右外连接：right [outer] join

 

错误语法:

              outer join

              full outer join

 

mysql不支持全连接

         全连接实现方法

  

select a.*,b.* from a left join b on a.id=b.id

union

select a.*,b.* from a right join b on a.id=b.id and a.id is null