如何在 MySQL 中执行多个选择查询?
如需在 MySQL 中执行多个选择查询,请使用 DELIMITER 这一概念。让我们先创建一个表——
mysql> create table DemoTable1 ( Title text )ENGINE=MyISAM; Query OK, 0 rows affected (0.30 sec)
使用插入命令向表中插入一些记录——
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)
使用选择语句从表中显示所有记录——
mysql> select *from DemoTable1;
这将生成以下输出——
+-------------------------------------------------+ | 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)
使用插入命令向表中插入一些记录——
mysql> insert into DemoTable2 values(),(),(),(),(),(),(),(),(); Query OK, 9 rows affected (0.19 sec) Records: 9 Duplicates: 0 Warnings: 0
使用选择语句从表中显示所有记录——
mysql> select *from DemoTable2;
这将生成以下输出——
+----+ | 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; //
这将生成以下输出,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)
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