如何在MySQL计算中使用别名？
让我们首先创建表。创建表的查询如下-
mysql> create table AliasDemo −> ( −> Id int −> );
借助insert命令将一些记录插入表中。以下是插入记录的查询-
mysql> insert into AliasDemo values(20); mysql> insert into AliasDemo values(30); mysql> insert into AliasDemo values(40);
现在您可以在select语句的帮助下显示所有记录-
mysql> select *from AliasDemo;
以下是输出-
+------+ | Id | +------+ | 20 | | 30 | | 40 | +------+ 3 rows in set (0.00 sec)
这是在计算中设置别名的查询-
mysql> select Id,100 as MyNumber ,(select MyNumber)*Id as MultiplyWith100 from AliasDemo;
以下是输出-
+------+----------+-----------------+ | Id | MyNumber | MultiplyWith100 | +------+----------+-----------------+ | 20 | 100 | 2000 | | 30 | 100 | 3000 | | 40 | 100 | 4000 | +------+----------+-----------------+ 3 rows in set (0.00 sec)
您可以一次执行。查询如下-
mysql> select 100 as MyNumber,(select MyNumber)*10 as MultiplyWith100;
以下是输出-
+----------+-----------------+ | MyNumber | MultiplyWith100 | +----------+-----------------+ | 100 | 1000 | +----------+-----------------+ 1 row in set (0.00 sec)