mysql的几种join方法详解

左连接

select from table_A A left join table_B B on A.key = B.key

注意此时当右边表里面没有此list内容时,内容会以null的形式显示

右连接

select from table_A A right join table_B B on A.key = B.key

注意此时当左边表里面没有此list内容时,内容会以null的形式显示

外连接

select from table_A A full out join table_B B on A.key = B.key

内连接

select from table_A A inter join table_B B on A.key = B.key

左内连接

select from table_A A left join table_B B on A.key = B.key where B.key is null

右内连接

select from table_A A left join table_B B on A.key = B.key where A.key is null

外连接-内连接

select from table_A A full out join table_B B on A.key = B.key where A.key is null or B.key is null