当列必须满足 MySQL 中的多个值时，如何选择行?
mysqlmysqli database更新于 2024/1/9 13:39:00
为此，您可以将 GROUP BY HAVING 子句与 IN() 一起使用。让我们首先创建一个表 −
mysql> create table DemoTable1885 ( FirstName varchar(20), Subject varchar(50) ); Query OK, 0 rows affected (0.00 sec)
使用 insert 命令在表中插入一些记录 −
mysql> insert into DemoTable1885 values('John','MySQL');
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1885 values('John','MongoDB');
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1885 values('Carol','MySQL');
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1885 values('David','Java');
Query OK, 1 row affected (0.00 sec)
使用 insert 命令显示表中的一些记录 −
mysql> select * from DemoTable1885;
这将产生以下输出 −
+-----------+---------+ | FirstName | Subject | +-----------+---------+ | John | MySQL| | John | MongoDB| | Carol | MySQL| | David | Java | +-----------+---------+ 4 rows in set (0.00 sec)
当列必须满足多个值时，这是选择行的查询:
mysql> select FirstName from DemoTable1885
where Subject IN('MySQL','MongoDB')
group by FirstName
having count(*)=2;
这将产生以下输出 −
+-----------+ | FirstName | +-----------+ | John | +-----------+ 1 row in set (0.00 sec)
