sql server的关联查询

Posted 2020-12-16 ryk72835

交叉关联

user_00

user_02

 

1 /*交叉关联*/ 
2 SELECT * FROM user_00 a
3 INNER JOIN user_02 b
4 ON a.id=b.id

左关联查询

1 SELECT * FROM user_00 a
2 LEFT JOIN user_02 b
3 ON a.id=b.id

右关联查询

1 SELECT * FROM user_00 a
2 RIGHT JOIN user_02 b
3 ON a.id=b.id

多表的关联查询

user_01

1 SELECT * FROM user_00 a
2 LEFT JOIN user_02 b
3 ON a.id=b.id
4 LEFT JOIN user_01 c
5 ON a.id=c.id

1 SELECT a.id,a.name,a.age,b.gender,c.course,c.course_time  FROM user_00 a
2 LEFT JOIN user_02 b
3 ON a.id=b.id
4 LEFT JOIN user_01 c
5 ON a.id=c.id
6 WHERE a.id=\'04183002\'