我们可以在单个MySQL查询中使用WHERE，AND和OR吗？
是的，我们可以在一个查询中使用所有它们。让我们首先创建一个表-
mysql> create table DemoTable ( StudentId int, StudentFirstName varchar(20), StudentLastName varchar(20), StudentAge int );
使用插入命令在表中插入记录-
mysql> insert into DemoTable values(100,'John','Smith',23); mysql> insert into DemoTable values(101,'Carol','Taylor',24); mysql> insert into DemoTable values(103,'John','Doe',22); mysql> insert into DemoTable values(104,'Adam','Smith',23);
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MySQLWHERE和AND或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)