oracle的全连接查询可以直接用full on,但是在mysql中没有full join,mysql使用union实现全连接.

 

oracle的全连接

select * from a full join b on a.id = b.id;

mysql的全连接

select * from a left join b on a.id = b.id union select * from a right join b on a.id = b.id;