如何在 MySQL 中执行多个选择查询?
mysqlmysqli database
要在 MySQL 中执行多个选择查询，请使用 DELIMITER 的概念。让我们首先创建一个表 −
mysql> create table DemoTable1 ( Title text )ENGINE=MyISAM; Query OK, 0 rows affected (0.30 sec)
使用 insert 命令在表中插入一些记录 −
mysql> insert into DemoTable1 values('The database MySQL is less popular than MongoDB') ;
Query OK, 1 row affected (0.09 sec)
mysql> insert into DemoTable1 values('Java language uses MySQL database');
Query OK, 1 row affected (0.05 sec)
mysql> insert into DemoTable1 values('Node.js uses the MongoDB') ;
Query OK, 1 row affected (0.05 sec)
使用 select 语句显示表中的所有记录 −
mysql> select *from DemoTable1;
这将产生以下输出 −
+-------------------------------------------------+ | Title | +-------------------------------------------------+ | The database MySQL is less popular than MongoDB | | Java language uses MySQL database | | Node.js uses the MongoDB | +-------------------------------------------------+ 3 rows in set (0.00 sec)
以下是创建第二个表的查询 −
mysql> create table DemoTable2 ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY ); Query OK, 0 rows affected (0.45 sec)
使用 insert 命令在表中插入一些记录 −
mysql> insert into DemoTable2 values(),(),(),(),(),(),(),(),(); Query OK, 9 rows affected (0.19 sec) Records: 9 Duplicates: 0 Warnings: 0
使用 select 语句显示表中的所有记录 −
mysql> select *from DemoTable2;
这将产生以下输出 −
+----+ | Id | +----+ | 1 | | 2 | | 3 | | 4 | | 5 | | 6 | | 7 | | 8 | | 9 | +----+ 9 rows in set (0.00 sec)
以下是执行多个选择查询的查询 −
mysql> DELIMITER // mysql> select *from DemoTable1; select *from DemoTable2; //
这将产生以下输出，显示两个选择语句的结果 −
+-------------------------------------------------+ | Title | +-------------------------------------------------+ | The database MySQL is less popular than MongoDB | | Java language uses MySQL database | | Node.js uses the MongoDB | +-------------------------------------------------+ 3 rows in set (0.00 sec) +----+ | Id | +----+ | 1 | | 2 | | 3 | | 4 | | 5 | | 6 | | 7 | | 8 | | 9 | +----+ 9 rows in set (0.03 sec)
