透過單個 MySQL 查詢按兩個欄位的功能排序

我們先建立一個表

mysql> create table orderByAFunctionDemo
   -> (
   -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,
   -> FirstNumber int,
   -> SecodNumber int
   -> );
Query OK, 0 rows affected (0.44 sec)

使用 insert 命令向表中插入一些記錄。查詢如下 -

mysql> insert into orderByAFunctionDemo(FirstNumber,SecodNumber) values(10,4);
Query OK, 1 row affected (0.11 sec)
mysql> insert into orderByAFunctionDemo(FirstNumber,SecodNumber) values(45,78);
Query OK, 1 row affected (0.17 sec)
mysql> insert into orderByAFunctionDemo(FirstNumber,SecodNumber) values(23,10);
Query OK, 1 row affected (0.12 sec)
mysql> insert into orderByAFunctionDemo(FirstNumber,SecodNumber) values(67,237);
Query OK, 1 row affected (0.16 sec)
mysql> insert into orderByAFunctionDemo(FirstNumber,SecodNumber) values(12,90);
Query OK, 1 row affected (0.13 sec)

使用 select 語句從表中顯示所有記錄。查詢如下 -

mysql> select *from orderByAFunctionDemo;

以下為輸出

+----+-------------+-------------+
| Id | FirstNumber | SecondNumber|
+----+-------------+-------------+
|  1 |          10 |           4 |
|  2 |          45 |          78 |
|  3 |          23 |          10 |
|  4 |          67 |         237 |
|  5 |          12 |          90 |
+----+-------------+-------------+
5 rows in set (0.00 sec)

以下是按兩個欄位的功能排序的查詢。查詢如下 -

mysql> select (4*FirstNumber+5*SecondNumber) as Calculation
   -> from orderByAFunctionDemo
   -> order by Calculation desc;

以下為輸出

+-------------+
| Calculation |
+-------------+
|        1453 |
|         570 |
|         498 |
|         142 |
|          60 |
+-------------+
5 rows in set (0.00 sec)

更新於： 30-Jul-2019

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