在MySQL中为自定义列设置多个值？
为此，您可以使用UNIONALL。让我们首先创建一个表-
mysql> create table DemoTable1987 ( UserValue int );
使用插入命令在表中插入一些记录-
mysql> insert into DemoTable1987 values(4); mysql> insert into DemoTable1987 values(5); mysql> insert into DemoTable1987 values(6); mysql> insert into DemoTable1987 values(7);
使用select语句显示表中的所有记录-
mysql> select * from DemoTable1987;
这将产生以下输出-
+-----------+ | UserValue | +-----------+ | 4 | | 5 | | 6 | | 7 | +-----------+ 4 rows in set (0.00 sec)
这是为自定义列设置多个值的查询-
mysql> select UserValue,(UserValue*100) as NewValue from DemoTable1987
union all
select UserValue,(UserValue*50) as NewValue from DemoTable1987
order by UserValue;这将产生以下输出-
+-----------+----------+ | UserValue | NewValue | +-----------+----------+ | 4 | 400 | | 4 | 200 | | 5 | 500 | | 5 | 250 | | 6 | 300 | | 6 | 600 | | 7 | 350 | | 7 | 700 | +-----------+----------+ 8 rows in set (0.14 sec)