Question

我有一个看起来像这样的数据集：

 Category    Date
 --------    ----
 Backlog     7/18/18
 Backlog     7/18/18
 Testing     7/18/18
 Done        7/18/18
 Backlog     7/19/18
 Develop     7/19/18
 Backlog     7/20/18
 Done        7/20/18
 Done        7/20/18

我想通过计数/组织来转变：

 Backlog     Testing    Develop    Done     Date
 -------     -------    -------    ----     ----
    2           1          0        1      7/18/18
    2           0          1        0      7/19/18
    1           0          0        2      7/20/18

但是，原始数据集每天仍在更新并带有新日期。第二天，将使用Backlog / Develop / Testing / Done标签（日期为7/21/18）将几行添加到表中。如何在sql中创建此转换，同时又考虑到数据集每天都会更新的事实？

Answer 1

您需要条件聚合：

select sum(Category = 'Backlog') as Backlog, 
       sum(Category = 'Testing') as Testing,
       sum(Category = 'Develop') as Develop,
       sum(Category = 'Done') as Done,
       date
from table t
group by date;

Answer 2

select *
from 
(
  select  Category,count(Category) as Total,Date
  from yourTableName group by Date,Category
) src
pivot
(
  sum(total)
  for Category in ([Backlog],[DONE],[Testing])
) piv;

输出将是这样的：

Date1       Backlog DONE    Testing
2018-07-18  2       1        1
2018-07-19  2       NULL    NULL
2018-07-20  NULL    2       NULL

在SQL中根据日期组织数据

2 个答案: