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  SQL - 排序结果

  • 简述

    SQLORDER BY子句用于根据一列或多列按升序或降序对数据进行排序。一些数据库默认按升序对查询结果进行排序。

  • 句法

    ORDER BY 子句的基本语法将用于按升序或降序对结果进行排序，如下所示 - 
    
SELECT column-list 
FROM table_name 
[WHERE condition] 
[ORDER BY column1, column2, .. columnN] [ASC | DESC];
    您可以在 ORDER BY 子句中使用多个列。确保无论您使用什么列进行排序，该列都应该在列列表中。

  • 例子

    考虑具有以下记录的 CUSTOMERS 表 - 
    
+----+----------+-----+-----------+----------+
| 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 |
+----+----------+-----+-----------+----------+
    以下是一个示例，它将按 NAME 和 SALARY 以升序对结果进行排序。 
    
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 |
+----+----------+-----+-----------+----------+
    以下代码块有一个示例，它将按 NAME 以降序对结果进行排序。 
    
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 |
+----+----------+-----+-----------+----------+
    要以自己的首选顺序获取行，使用的 SELECT 查询如下 - 
    
SQL> SELECT * FROM CUSTOMERS
   ORDER BY (CASE ADDRESS
   WHEN 'DELHI'    THEN 1
   WHEN 'BHOPAL'   THEN 2
   WHEN 'KOTA'     THEN 3
   WHEN 'AHMEDABAD' 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 |
+----+----------+-----+-----------+----------+
    这将按 ADDRESS 对客户进行排序ownoOrder优先，其余地址按自然顺序排列。此外，其余地址将按字母倒序排列。
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