Question

您好我正在尝试清理查询，并且有一行重复六次。有没有办法在SQL中设置类似常量的东西？

以下是此问题的示例：

select Distinct DSF.CityName, 
( Select count (Distinct DSF1.IncdtKey)
  from dbo.IncidentFile DSF1 
  Where DSF1.IncidentMostSevere in ('1', '2', '4', '5', '6')
  and DSF1.CategoryKey in ('15', '01', '02', '03', '04', '05', '06')<-----
  and DSF1.CityName = DSF.CityName)  as 'Weapons Possession 11-12',
( Select count (Distinct DSF2.IncdtKey)
  from dbo.IncidentFile DSF2 
  Where DSF2.IncidentMostSevere in ('7', '8', '9', '10', '11', '12')
  and DSF2.CategoryKey in ('15', '01', '02', '03', '04', '05', '06') <-----
  and DSF2.CityName = DSF.CityName)  as 'Drugs Related 11-12',
( Select count (Distinct DSF3.IncdtKey)
  from dbo.IncidentFile DSF3 
  Where DSF3.IncidentMostSevere in ('14', '15', '17', '20', '21', '22', '26') 
  and DSF3.CategoryKey in ('15', '01', '02', '03', '04', '05', '06') <-----
  and DSF3.CityName = DSF.CityName)  as 'Incident with Injury 11-12',
( Select count (Distinct DSF4.IncdtKey)
  from dbo.IncidentFile DSF4 
  Where DSF4.IncidentMostSevere in ('16', '18', '19', '23', '24', '25')
  and DSF4.CategoryKey in ('15', '01', '02', '03', '04', '05', '06') <-----
  and DSF4.CityName = DSF.CityName)  as 'Incident no Injury 11-12',
( Select count (Distinct DSF5.IncdtKey)
  from dbo.IncidentFile DSF5 
  Where DSF5.IncidentMostSevere in ('3', '13', '29', '31', '32', '33')
 and DSF5.CategoryKey in ('15', '01', '02', '03', '04', '05', '06') <-----
 and DSF5.CityName = DSF.CityName)  as 'Other reason for 11-12',
( Select count (Distinct DSF6.IncdtKey)
  from dbo.IncidentFile DSF6 
  Where DSF6.CategoryKey in ('15', '01', '02', '03', '04', '05', '06') <-----
  and DSF6.CityName = DSF.CityName)  as 'Total Incidents'
  from dbo.IncidentFile DSF
group by DSF.CityName
Order by DSF.CityName

由于

Answer 1

您应该能够使用CTE，然后使用带有CASE表达式的聚合函数：

;with cte as
(
  select distinct CityName,
    IncidentMostSevere,
     IncdtKey
  from dbo.IncidentFile
  where CategoryKey in ('15', '01', '02', '03', '04', '05', '06')
)
select CityName,
  count(case 
        when IncidentMostSevere in ('1', '2', '4', '5', '6')
        then IncdtKey end) as 'Weapons Possession 11-12',
  count(case 
        when IncidentMostSevere in ('7', '8', '9', '10', '11', '12')
        then IncdtKey end) as 'Drugs Related 11-12',
  count(case 
        when IncidentMostSevere in ('14', '15', '17', '20', '21', '22', '26')
        then IncdtKey end) as 'Incident with Injury 11-12',
  count(case 
        when IncidentMostSevere in ('16', '18', '19', '23', '24', '25')
        then IncdtKey end) as 'Incident no Injury 11-12',
  count(case 
        when IncidentMostSevere in ('3', '13', '29', '31', '32', '33')
        then IncdtKey end) as 'Other reason for 11-12',
  count(case 
        when IncidentMostSevere in ('15', '01', '02', '03', '04', '05', '06')
        then IncdtKey end) as 'Total Incidents'
from cte
group by CityName
order by CityName

Answer 2

此方法的工作原理是将子查询移动到from子句中，并在where子句中添加一次类别列表。

select 
  DSF.CityName, 
  Dsf1.cnt as 'Weapons Possession 11-12',
  Dsf2.cnt as 'Drugs Related 11-12',
  ...
  Dfsn.cnt as 'Total Incidents'

From
  dbo.IncidentFile DSF

  Inner join
  (
     Select 
       DSF.CategoryKey,
       DSF.CityName,
       count (Distinct DSF.IncdtKey) as cnt
     from 
       dbo.IncidentFile DSF
     Where
       DSF.IncidentMostSevere in ('1', '2', '4', '5', '6').  
     group by
       1, 2
   ) DSF1
   On  DSF1.CityName = DSF.CityName

   Inner join
   ( 
     Select 
       DSF.CategoryKey,
       DSF.CityName,
       count (Distinct DSF.IncdtKey) as cnt
     from 
       dbo.IncidentFile DSF
     Where
       DSF.IncidentMostSevere in ('7', '8', '9', '10', '11', '12') 
     group by
       1, 2
   ) DSF2
   On DSF2.CityName = DSF.CityName 

   ...

   Inner join
   ( 
     Select 
       DSF.CategoryKey,
       DSF.CityName,
       count (Distinct DSF.IncdtKey) as cnt
     from 
       dbo.IncidentFile DSF
     Where
       DSF.IncidentMostSevere in ('7', '8', '9', '10', '11', '12') 
     group by
       1, 2
   ) DSFn
   On dfsn.CityName = DSF.CityName   

 Where 
   dfsn.CategoryKey in ('15','01','02,'03','04','05','06')


 Order by DSF.CityName

SQL Server可以解决重复的条件行问题

2 个答案: