MySQL 中两列的有序差值？

对此使用 ORDER BY 子句。让我们首先创建一个表 −

mysql> create table DemoTable
   (
   Value1 int,
   Value2 int
   );
Query OK, 0 rows affected (0.54 sec)

使用 insert 命令在表中插入一些记录 −

mysql> insert into DemoTable values(10,40);
Query OK, 1 row affected (0.20 sec)
mysql> insert into DemoTable values(50,5);
Query OK, 1 row affected (0.13 sec)
mysql> insert into DemoTable values(51,56);
Query OK, 1 row affected (0.18 sec)
mysql> insert into DemoTable values(52,78);
Query OK, 1 row affected (0.16 sec)
mysql> insert into DemoTable values(90,7);
Query OK, 1 row affected (0.21 sec)

使用 select 语句从表中显示所有记录 −

mysql> select *from DemoTable;

输出

+--------+--------+
| Value1 | Value2 |
+--------+--------+
| 10     | 40     |
| 50     | 5      |
| 51     | 56     |
| 52     | 78     |
| 90     | 7      |
+--------+--------+
5 rows in set (0.00 sec)

以下是获取两个列之间有序差值的查询 −

mysql> select (Value1-Value2) as Sub from DemoTable order by Sub DESC;

输出

+------+
| Sub  |
+------+
| 83   |
| 45   |
| -5   |
| -26  |
| -30  |
+------+
5 rows in set (0.00 sec)

Chandu yadav

更新于： 30-Jul-2019

423 浏览量

开启 你的职业生涯

完成课程，获得认证

开始学习