SQL table Connection Query

Two tables:

1Mysql> Select *  fromstudent;2 +----+------+------+3 |Id|Name|Age|4 +----+------+------+5 |  1 |Xiao Wang|    - |6 |  2 |Little Red|    - |7 |  3 |Xiao ming|    - |8 |  4 |Xiao Li|    A |9 |  5 |Jack bauer|    - |Ten +----+------+------+ One 5Rowsinch Set(0.00Sec

1Mysql> Select *  fromMark;2 +----+------+-----------+3 |Id|Mark|StudentID|4 +----+------+-----------+5 |  1 |    A |         2 |6 |  2 |    $ |         2 |7 |  3 |    - |         3 |8 +----+------+-----------+9 3Rowsinch Set(0.00Sec

One, inner connection (inner join)

1Mysql> SelectS.name,m.mark fromStudent S,mark mwhereS.id=M.studentid;2 +------+------+3 |Name|Mark|4 +------+------+5 |Little Red|    A |6 |Little Red|    $ |7 |Xiao ming|    - |8 +------+------+9 3Rowsinch Set(0.07sec)TenMysql> SelectS.name,m.mark fromStudent SInner JoinMark M onS.id=M.studentid; One +------+------+ A |Name|Mark| - +------+------+ - |Little Red|    A | the |Little Red|    $ | - |Xiao ming|    - | - +------+------+ - 3Rowsinch Set(0.06Sec

Second, left join (left join)

1Mysql> SelectS.name,m.mark fromStudent S Left JoinMark M onS.id=M.studentid;2 +------+------+3 |Name|Mark|4 +------+------+5 |Little Red|    A |6 |Little Red|    $ |7 |Xiao ming|    - |8 |Xiao Wang| NULL |9 |Xiao Li| NULL |Ten |Jack bauer| NULL | One +------+------+ A 6Rowsinch Set(0.07Sec

Third, right Join

1Mysql> SelectS.name,m.mark fromStudent S Right JoinMark M onS.id=M.studentid;2 +------+------+3 |Name|Mark|4 +------+------+5 |Little Red|    A |6 |Little Red|    $ |7 |Xiao ming|    - |8 +------+------+9 3Rowsinch Set(0.00Sec

SQL table Connection Query