MySQL ORDER BY用法及代码示例

MySQL 的 ORDER BY 子句对检索到的记录进行排序，并默认按升序返回它们。如果需要的话，我们可以指定按降序排序。

用法

SELECT column_name(s)
FROM table_name
ORDER BY column1, column2 (DESC);

例子

考虑下表有关一些学生的信息：

student_id	名称	名字	day_enrolled	年龄	用户名
1	Sky	Towner	2015-12-03	17	stowner1
2	Ben	Davis	2016-04-20	19	bdavis2
3	Travis	Apple	2018-08-14	18	tapple3
4	Arthur	David	2016-04-01	16	adavid4
5	Benjamin	Town	2014-01-01	17	btown5

可以使用此处的代码创建上述示例表。

升序

要按 age 升序对学生进行排序：

SELECT * FROM students
ORDER BY age;



+------------+----------+--------+--------------+------+----------+
| student_id | fname    | lname  | day_enrolled | age  | username |
+------------+----------+--------+--------------+------+----------+
|          4 | Arthur   | David  | 2016-04-01   |   16 | adavid4  |
|          1 | Sky      | Towner | 2015-12-03   |   17 | stowner1 |
|          5 | Benjamin | Town   | 2014-01-01   |   17 | btown5   |
|          3 | Travis   | Apple  | 2018-08-14   |   18 | tapple3  |
|          2 | Ben      | Davis  | 2016-04-20   |   19 | bdavis2  |
+------------+----------+--------+--------------+------+----------+

降序

要按 age 降序对学生进行排序：

SELECT * FROM students
ORDER BY age DESC;



+------------+----------+--------+--------------+------+----------+
| student_id | fname    | lname  | day_enrolled | age  | username |
+------------+----------+--------+--------------+------+----------+
|          2 | Ben      | Davis  | 2016-04-20   |   19 | bdavis2  |
|          3 | Travis   | Apple  | 2018-08-14   |   18 | tapple3  |
|          1 | Sky      | Towner | 2015-12-03   |   17 | stowner1 |
|          5 | Benjamin | Town   | 2014-01-01   |   17 | btown5   |
|          4 | Arthur   | David  | 2016-04-01   |   16 | adavid4  |
+------------+----------+--------+--------------+------+----------+

按字母顺序

根据学生名字的字母顺序对学生进行排序：

SELECT * FROM students
WHERE fname is NOT NULL
ORDER BY fname;



+------------+----------+--------+--------------+------+----------+
| student_id | fname    | lname  | day_enrolled | age  | username |
+------------+----------+--------+--------------+------+----------+
|          4 | Arthur   | David  | 2016-04-01   |   16 | adavid4  |
|          2 | Ben      | Davis  | 2016-04-20   |   19 | bdavis2  |
|          5 | Benjamin | Town   | 2014-01-01   |   17 | btown5   |
|          1 | Sky      | Towner | 2015-12-03   |   17 | stowner1 |
|          3 | Travis   | Apple  | 2018-08-14   |   18 | tapple3  |
+------------+----------+--------+--------------+------+----------+

对多列进行排序

对于具有相同 age 的学生，按照 age 的升序排列学生，然后按照 fname 的降序排列：

SELECT * 
FROM students
WHERE fname is NOT NULL
ORDER BY age, fname DESC;



+------------+----------+--------+--------------+------+----------+
| student_id | fname    | lname  | day_enrolled | age  | username |
+------------+----------+--------+--------------+------+----------+
|          4 | Arthur   | David  | 2016-04-01   |   16 | adavid4  |
|          1 | Sky      | Towner | 2015-12-03   |   17 | stowner1 |
|          5 | Benjamin | Town   | 2014-01-01   |   17 | btown5   |
|          3 | Travis   | Apple  | 2018-08-14   |   18 | tapple3  |
|          2 | Ben      | Davis  | 2016-04-20   |   19 | bdavis2  |
+------------+----------+--------+--------------+------+----------+

当列条目具有重复数据时，对多列进行排序是有意义的(在这种情况下 'Sky' 和 'Benjamin' 都是 17 )。对于 'Sky' 和 'Benjamin'，我们然后根据 fname 的字母降序顺序确定它们的顺序，这就是为什么 'Sky' 在 'Benjamin' 之上返回。

相关用法

注：本文由纯净天空筛选整理自Arthur Yanagisawa大神的英文原创作品 MySQL | ORDER BY。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。