SQL语句--分组的Top查询

分组的Top查询：

代码

   
     

    
      
    
      SELECT
    
       ROW_NUMBER() 
    
      OVER
    
       (
    
      order
    
       
    
      by
    
       a.Host,EnterTimes 
    
      DESC
    
      )
    
      as
    
       RowNumber,

    
      --
    
      SELECT IDENTITY(int,1,1) as RowNumber,
    
      

    
      a.Host,a.PageURL,a.EnterTimes,a.BounceTimes 
    
      INTO
    
       #TempEntryUrlList

    
      FROM
    
      
(
 
    
      SELECT
    
       Host 
    
      --
    
      Host
    
      

    
       ,EntranceURL 
    
      as
    
       PageURL 
    
      --
    
      页面地址
    
      

    
       ,
    
      count
    
      (EntranceURL) 
    
      as
    
       EnterTimes 
    
      --
    
      进入次数
    
      

    
       ,
    
      sum
    
      (
    
      CASE
    
       
    
      WHEN
    
       IsBounce
    
      =
    
      1
    
       
    
      THEN
    
       
    
      1
    
       
    
      ELSE
    
       
    
      0
    
       
    
      END
    
       ) 
    
      AS
    
       BounceTimes 
    
      --
    
      跳出次数
    
      

    
       
    
      FROM
    
       UserLoyalty 
    
      WITH
    
      (nolock)
 
    
      GROUP
    
       
    
      BY
    
       Host,EntranceURL
) a
   
     

需要对以上#TempEntryUrlList临时表做查询：按照Host分组，查询每个Host的EnterTimes的Top 100数据：

代码

   
     

    
      
    
      Select
    
       
    
      *
    
      

    
      FROM
    
       #TempEntryUrlList A

    
      Where
    
       
    
      EXISTS
    
      
 (
    
      SELECT
    
       
    
      COUNT
    
      (
    
      1
    
      )
 
    
      FROM
    
       #TempEntryUrlList
 
    
      WHERE
    
       Host 
    
      =
    
       A.Host 
    
      AND
    
       RowNumber 
    
      <
    
       A.RowNumber
 
    
      HAVING
    
       
    
      COUNT
    
      (
    
      1
    
      ) 
    
      <
    
       
    
      100
    
      )

    
      ORDER
    
       
    
      BY
    
       Host,EnterTimes 
    
      DESC
    
       
   
     

 

补充：感谢“我爱菊花”的回复，用ROW_NUMBER的PARTITION属性就可以一句话实现，免去临时表:

代码

   
     

    
      
    
      SELECT
    
       A.
    
      *
    
      

    
      FROM
    
      
(
 
    
      SELECT
    
       ROW_NUMBER() 
    
      OVER
    
      (PARTITION 
    
      BY
    
       Host 
    
      ORDER
    
       
    
      BY
    
       Host,
    
      count
    
      (EntranceURL) 
    
      DESC
    
      ) 
    
      AS
    
       ROW,
 Host, 
 EntranceURL 
    
      as
    
       PageURL
 ,
    
      count
    
      (EntranceURL) 
    
      as
    
       EnterTimes
 ,
    
      sum
    
      (
    
      CASE
    
       
    
      WHEN
    
       IsBounce
    
      =
    
      1
    
       
    
      THEN
    
       
    
      1
    
       
    
      ELSE
    
       
    
      0
    
       
    
      END
    
       ) 
    
      AS
    
       BounceTimes
 
    
      FROM
    
       UserLoyalty
 
    
      GROUP
    
       
    
      BY
    
       Host,EntranceURL
) A

    
      WHERE
    
       A.ROW
    
      <=
    
      100
   
     

 

注：数据量大的话，感觉性能不是很好，数据量小的时候，还是可以用的。