如何在单个 MySQL 查询中使用三个条件(学生的 id、姓名和年龄)来获取学生的记录?
mysqlmysqli database
首先我们创建一个表 −
mysql> create table DemoTable ( StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, StudentName varchar(50), StudentAge int ); Query OK, 0 rows affected (0.72 sec)
使用 insert 命令在表中插入一些记录 −
mysql> insert into DemoTable(StudentName,StudentAge) values('Chris',21);
Query OK, 1 row affected (0.12 sec)
mysql> insert into DemoTable(StudentName,StudentAge) values('David',23);
Query OK, 1 row affected (0.14 sec)
mysql> insert into DemoTable(StudentName,StudentAge) values('Bob',22);
Query OK, 1 row affected (0.17 sec)
mysql> insert into DemoTable(StudentName,StudentAge) values('Carol',21);
Query OK, 1 row affected (0.30 sec)
使用 select 语句显示表中的所有记录 −
mysql> select *from DemoTable;
这将产生以下输出 &minusl;
+-----------+-------------+------------+ | StudentId | StudentName | StudentAge | +-----------+-------------+------------+ | 1 | Chris | 21 | | 2 | David | 23 | | 3 | Bob | 22 | | 4 | Carol | 21 | +-----------+-------------+------------+ 4 rows in set (0.00 sec)
以下是实现三个条件来获取特定记录的查询−
mysql> select *from DemoTable where StudentId=4 and StudentName='Carol' and StudentAge=21;
这将产生以下输出 −
+-----------+-------------+------------+ | StudentId | StudentName | StudentAge | +-----------+-------------+------------+ | 4 | Carol | 21 | +-----------+-------------+------------+ 1 row in set (0.00 sec)
