Question

数据库中的表格就像这种格式

 id    Name         Month   Spending

1001    Murphy      JAN       500
1001    Murphy      FEB       750
1001    Murphy      MAR       300
1002    Patterson   JAN       155
1002    Patterson   FEB       85
1002    Patterson   MAR       60
1003    Firrelli    JAN       125
1003    Firrelli    FEB       100
1003    Firrelli    MAR       250

对于图中的绘图数据，我需要像这样的查询结果..

id    name          JAN    FEB    MAR

1001   Murphy       500    750    300
1002   Patterson    155    85     60
1003   Firrelli     125    100    250

是否可以获得这样的查询结果？

无需创建表，只需查询结果。

Answer 1

使用Conditional Aggregate将行转置为列。试试这个。

select id,Name,
max(case when Month ='Jan' then Spending end) Jan,
max(case when Month ='Feb' then Spending end) Feb,
max(case when Month ='Mar' then Spending end) Mar
from yourtable
group by id,Name

Answer 2

如果月数是静态的，可以通过多种方式完成，例如：

SELECT id, Name, SUM(JAN) AS JAN, SUM(FEB) AS FEB, SUM(MAR) AS MAR
FROM
  (SELECT id, name, Spending AS JAN, 0 AS FEB, 0 AS MAR
  FROM t1
  WHERE Month = 'JAN'
  UNION ALL
  SELECT id, name, 0, Spending, 0
  FROM t1
  WHERE Month = 'FEB'
  UNION ALL
  SELECT id, name, 0, 0, Spending
  FROM t1
  WHERE Month = 'MAR')
GROUP BY id, Name

是否可以将结果列名称作为行值查询？

2 个答案: