SQL ORDER BY子句用于对数据根据一个或一个以上的列按升序或降序进行排序。一些数据库默认排序查询结果按升序排列。
ORDER BY子句的基本语法,将用于在升序或降序排列结果如下:
SELECT column-list
FROM table_name
[WHERE condition]
[ORDER BY column1, column2, .. columnN] [ASC | DESC];
您可以在ORDER BY子句中使用多列。确保不管使用的是排序什么列,此列应该在 column-list 中。
考虑CUSTOMERS表具有以下记录:
+----+----------+-----+-----------+----------+
| ID | NAME | AGE | ADDRESS | SALARY |
+----+----------+-----+-----------+----------+
| 1 | Ramesh | 32 | Ahmedabad | 2000.00 |
| 2 | Khilan | 25 | Delhi | 1500.00 |
| 3 | kaushik | 23 | Kota | 2000.00 |
| 4 | Chaitali | 25 | Mumbai | 6500.00 |
| 5 | Hardik | 27 | Bhopal | 8500.00 |
| 6 | Komal | 22 | MP | 4500.00 |
| 7 | Muffy | 24 | Indore | 10000.00 |
+----+----------+-----+-----------+----------+
下面是一个例子,这将结果通过NAME和SALARY按升序排序:
SQL> SELECT * FROM CUSTOMERS
ORDER BY NAME, SALARY;
这将产生以下结果:
+----+----------+-----+-----------+----------+
| ID | NAME | AGE | ADDRESS | SALARY |
+----+----------+-----+-----------+----------+
| 4 | Chaitali | 25 | Mumbai | 6500.00 |
| 5 | Hardik | 27 | Bhopal | 8500.00 |
| 3 | kaushik | 23 | Kota | 2000.00 |
| 2 | Khilan | 25 | Delhi | 1500.00 |
| 6 | Komal | 22 | MP | 4500.00 |
| 7 | Muffy | 24 | Indore | 10000.00 |
| 1 | Ramesh | 32 | Ahmedabad | 2000.00 |
+----+----------+-----+-----------+----------+
下面是一个例子,这将结果按NAME降序排序:
SQL> SELECT * FROM CUSTOMERS
ORDER BY NAME DESC;
这将产生以下结果:
+----+----------+-----+-----------+----------+
| ID | NAME | AGE | ADDRESS | SALARY |
+----+----------+-----+-----------+----------+
| 1 | Ramesh | 32 | Ahmedabad | 2000.00 |
| 7 | Muffy | 24 | Indore | 10000.00 |
| 6 | Komal | 22 | MP | 4500.00 |
| 2 | Khilan | 25 | Delhi | 1500.00 |
| 3 | kaushik | 23 | Kota | 2000.00 |
| 5 | Hardik | 27 | Bhopal | 8500.00 |
| 4 | Chaitali | 25 | Mumbai | 6500.00 |
+----+----------+-----+-----------+----------+
获取使用自己的优先顺序行,SELECT查询将如下:
SQL> SELECT * FROM CUSTOMERS
ORDER BY (CASE ADDRESS
WHEN 'DELHI' THEN 1
WHEN 'BHOPAL' THEN 2
WHEN 'KOTA' THEN 3
WHEN 'AHMADABAD' THEN 4
WHEN 'MP' THEN 5
ELSE 100 END) ASC, ADDRESS DESC;
这将产生以下结果:
+----+----------+-----+-----------+----------+
| ID | NAME | AGE | ADDRESS | SALARY |
+----+----------+-----+-----------+----------+
| 2 | Khilan | 25 | Delhi | 1500.00 |
| 5 | Hardik | 27 | Bhopal | 8500.00 |
| 3 | kaushik | 23 | Kota | 2000.00 |
| 6 | Komal | 22 | MP | 4500.00 |
| 4 | Chaitali | 25 | Mumbai | 6500.00 |
| 7 | Muffy | 24 | Indore | 10000.00 |
| 1 | Ramesh | 32 | Ahmedabad | 2000.00 |
+----+----------+-----+-----------+----------+
这将在你自己喜欢的顺序首先在一个自然顺序,对剩余的地址按客户的ADDRESS进行排序。同时剩余的地址将在相反的字母顺序进行排序。