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      PostgreSQL order by

      PostgreSQL ORDER BY 语句

      在 PostgreSQL 中,ORDER BY 用于对一列或者多列数据进行升序(ASC)或者降序(DESC)排列。

      语法

      ORDER BY 子句的基础语法如下:

      SELECT column-list
      FROM table_name
      [WHERE condition]
      [ORDER BY column1, column2, .. columnN] [ASC | DESC];
      

      您可以在 ORDER BY 中使用一列或者多列,但是必须保证要排序的列必须存在。

      ASC 表示升序,DESC 表示降序。

      实例

      创建 COMPANY 表,数据内容如下:

      axihedb# select * from COMPANY;
       id | name  | age | address   | salary
      ----+-------+-----+-----------+--------
        1 | Paul  |  32 | California|  20000
        2 | Allen |  25 | Texas     |  15000
        3 | Teddy |  23 | Norway    |  20000
        4 | Mark  |  25 | Rich-Mond |  65000
        5 | David |  27 | Texas     |  85000
        6 | Kim   |  22 | South-Hall|  45000
        7 | James |  24 | Houston   |  10000
      (7 rows)
      

      下面实例将对结果根据 AGE 字段值进行升序排列:

      axihedb=# SELECT * FROM COMPANY ORDER BY AGE ASC;
      

      得到以下结果:

       id | name  | age |                      address                       | salary
      ----+-------+-----+----------------------------------------------------+--------
        6 | Kim   |  22 | South-Hall                                         |  45000
        3 | Teddy |  23 | Norway                                             |  20000
        7 | James |  24 | Houston                                            |  10000
        4 | Mark  |  25 | Rich-Mond                                          |  65000
        2 | Allen |  25 | Texas                                              |  15000
        5 | David |  27 | Texas                                              |  85000
        1 | Paul  |  32 | California                                         |  20000
      (7 rows)
      
      

      下面实例将对结果根据 NAME 字段值和 SALARY 字段值进行升序排序:

      axihedb=# SELECT * FROM COMPANY ORDER BY NAME, SALARY ASC;
      

      得到以下结果:

       id | name  | age |                      address                       | salary
      ----+-------+-----+----------------------------------------------------+--------
        2 | Allen |  25 | Texas                                              |  15000
        5 | David |  27 | Texas                                              |  85000
        7 | James |  24 | Houston                                            |  10000
        6 | Kim   |  22 | South-Hall                                         |  45000
        4 | Mark  |  25 | Rich-Mond                                          |  65000
        1 | Paul  |  32 | California                                         |  20000
        3 | Teddy |  23 | Norway                                             |  20000
      (7 rows)
      

      下面实例将对结果根据 NAME 字段值进行降序排列:

      axihedb=# SELECT * FROM COMPANY ORDER BY NAME DESC;
      

      得到以下结果:

       id | name  | age |                      address                       | salary
      ----+-------+-----+----------------------------------------------------+--------
        3 | Teddy |  23 | Norway                                             |  20000
        1 | Paul  |  32 | California                                         |  20000
        4 | Mark  |  25 | Rich-Mond                                          |  65000
        6 | Kim   |  22 | South-Hall                                         |  45000
        7 | James |  24 | Houston                                            |  10000
        5 | David |  27 | Texas                                              |  85000
        2 | Allen |  25 | Texas                                              |  15000
      (7 rows)
      
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