2011-03-19 09:46:18 0 评论 MySQL Boy.Lee

MySQL left or right or inner or cross join Statements Example

SQL query: SELECT * FROM `user` LIMIT 0, 30 ; Rows: 2

id name
2 BoyLee
3 Gigi

    SQL query: SELECT * FROM `info` LIMIT 0, 30 ; Rows: 2

user_id address
3 China
4 Mars

      {Left Join} SQL query: select * from user as u left join info i on u.id = i.user_id where 1=1 LIMIT 0, 30 ;

Rows: 2

id name user_id address
2 BoyLee NULL NULL
3 Gigi 3 China

    {Right Join} SQL query: SELECT * FROM user AS u RIGHT JOIN info i ON u.id = i.user_id WHERE 1 =1 LIMIT 0 , 30; Rows: 2

id name user_id address
3 Gigi 3 China
NULL NULL 4 Mars

    {Inner Join} SQL query: SELECT * FROM user AS u, info i WHERE u.id = i.user_id AND 1 =1 LIMIT 0 , 30; Rows: 1

id name user_id address
3 Gigi 3 China

SQL query: SELECT * FROM user AS u INNER JOIN info i ON u.id = i.user_id WHERE 1 =1 LIMIT 0 , 30; Rows: 1

id name user_id address
3 Gigi 3 China

    {Cross Join} SQL query: SELECT * FROM user AS u CROSS JOIN info i ON u.id = i.user_id WHERE 1 =1 LIMIT 0 , 30; Rows: 1

id name user_id address
3 Gigi 3 China

  Code tell u every thing. ^&^