Question

我有一个数据库，其中包含如下表1所示的样本数据。如何编写SQL查询以表2或表3格式显示它们？

Table 1                         Table 2                      
Date        |  Value            Year  |  Week  |  Total Value  |  % Change               
------------+-------            ------+-----+--|---------------|----------
19/12/2011  |  60               2012  |    1   |      295      |  656.41%               
20/12/2011  |  49               2012  |    0   |       39      |  -80.98%               
21/12/2011  |  42               2012  |   52   |      205      |  -41.76%               
22/12/2011  |  57               2011  |   51   |      352      |                 
23/12/2011  |  88 
24/12/2011  |  18               Table 3                    
25/12/2011  |  38               Year  |  Week  |  SUM1  |  Year  |  Week  |  SUM2  |  % Change
26/12/2011  |  16               ------+--------+--------+--------+--------+--------+-----------
27/12/2011  |  66               2012  |    1   |   295  |  2012  |    0   |   39   |  656.41%
28/12/2011  |  21               2012  |    0   |    39  |  2011  |   52   |  205   |  -80.98%
29/12/2011  |  79               2011  |   52   |   205  |  2011  |   51   |  352   |  -41.76%              
30/12/2011  |  7                2011  |   51   |   352  |    
31/12/2011  |  16
01/01/2012  |  39
02/01/2012  |  17
03/01/2012  |  86 
04/01/2012  |  55
05/01/2012  |  82
06/01/2012  |  0
07/01/2012  |  9
08/01/2012  |  46

Answer 1

我的偏好是运行1个查询将表1汇总到年/周级别，然后根据您的环境用另一种语言执行“％change”。但是，如果您真的需要一个只有SQL的解决方案，那么您可以这样做。

create table t1 as
    select year(Date) as year, week(Date) as week, sum(Value) as totalvalue
    from table1
    group by year(Date) as year, week(Date) as week
    order by Date desc
;

select a.year, a.month, a.totalvalue,
(a.totalvalue-b.totalvalue)/b.totalvalue as pct_change
from (
  select year, month, totalvalue, 
  case when week>1 then week-1 else 52 end as prevweek,
  case when week>1 then year else year-1 end as prevyear
  from t1
  ) a
    left outer join t1 b
    on a.prevweek=b.week and a.prevyear =b.year
;

SQL Query显示％Change

1 个答案: