从表中选择MySQL不存在值的表？
对于这一点，你可以使用NOTIN()-
mysql> create table DemoTable1991 ( StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, StudentName varchar(20) );
使用插入命令在表中插入一些记录-
mysql> insert into DemoTable1991(StudentName) values('Chris');
mysql> insert into DemoTable1991(StudentName) values('Bob');
mysql> insert into DemoTable1991(StudentName) values('David');
mysql> insert into DemoTable1991(StudentName) values('Sam');
mysql> insert into DemoTable1991(StudentName) values('Mike');使用select语句显示表中的所有记录-
mysql> select * from DemoTable1991;
这将产生以下输出-
+-----------+-------------+ | StudentId | StudentName | +-----------+-------------+ | 1 | Chris | | 2 | Bob | | 3 | David | | 4 | Sam | | 5 | Mike | +-----------+-------------+ 5 rows in set (0.03 sec)
这是从不存在值的表中选择*的查询：
mysql> select * from DemoTable1991
where StudentName NOT IN('Bob','Sam','Mike');这将产生以下输出-
+-----------+-------------+ | StudentId | StudentName | +-----------+-------------+ | 1 | Chris | | 3 | David | +-----------+-------------+ 2 rows in set (0.04 sec)