我们可以在单个 MySQL 查询中使用 WHERE、AND 和 OR 吗?
mysqlmysqli database
是的，我们可以在单个查询中使用它们。让我们首先创建一个表 −
mysql> create table DemoTable ( StudentId int, StudentFirstName varchar(20), StudentLastName varchar(20), StudentAge int ); Query OK, 0 rows affected (0.53 sec)
使用 insert 命令在表中插入记录 −
mysql> insert into DemoTable values(100,'John','Smith',23); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values(101,'Carol','Taylor',24); Query OK, 1 row affected (0.62 sec) mysql> insert into DemoTable values(103,'John','Doe',22); Query OK, 1 row affected (0.24 sec) mysql> insert into DemoTable values(104,'Adam','Smith',23); Query OK, 1 row affected (0.18 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 −
+-----------+------------------+-----------------+------------+ | StudentId | StudentFirstName | StudentLastName | StudentAge | +-----------+------------------+-----------------+------------+ | 100 | John | Smith | 23 | | 101 | Carol | Taylor | 24 | | 103 | John | Doe | 22 | | 104 | Adam | Smith | 23 | +-----------+------------------+-----------------+------------+ 4 rows in set (0.00 sec)
以下是在单个 MySQL 查询中使用 MySQL WHERE、AND 和 OR 来获取记录的查询 −
mysql> select *from DemoTable where StudentFirstName='John' AND StudentLastName='Doe' OR StudentAge=26;
这将产生以下输出 −
+-----------+------------------+-----------------+------------+ | StudentId | StudentFirstName | StudentLastName | StudentAge | +-----------+------------------+-----------------+------------+ | 103 | John | Doe | 22 | +-----------+------------------+-----------------+------------+ 1 row in set (0.00 sec)
