mysql操作--连接查询

1.innerjoin（内连接,或等值连接）

select * from table1 inner join table2 on table1.column1= table2.column2;

2.left join（左连接）

select * from table1left join table2 on table1.column1= table2.column2;

3.right join（右连接）

select * from table1 right join table2 on table1.column1= table2.column2;

4.select并集

select * from table1left join table2 on table1.column1= table2.column2 union select * from table1 right join table2 on table1.column1= table2.column2;