数据仓库服务 GAUSSDB(DWS)-GaussDB(DWS)如何实现行转列及列转行？:列转行

时间：2024-06-21 18:00:22

列转行

使用union all，将各科目（math、physics和literature）整合为一列，示例如下：

  
   
     
     
       SELECT * FROM 
(
SELECT name, 'math' AS subject, math AS score FROM students_info1
union all
SELECT name, 'physics' AS subject, physics AS score FROM students_info1
union all
SELECT name, 'literature' AS subject, literature AS score FROM students_info1
) 
order by name;
 name |  subject   | score
------+------------+-------
 jack | math       |    90
 jack | physics    |    95
 jack | literature |    95
 lily | math       |    95
 lily | physics    |    80
 lily | literature |    92
 matu | math       |    75
 matu | physics    |    90
 matu | literature |    85
(9 rows)

      

    

  
 