在 SQL Azure“导入数据”中对表进行分组时编写数学公式

Question

This query is working fine

select OrderForSeries.memberid, 
       Orderforseries.seriesid  ,
       log(count(orderforcontent.id)) as rating,
       Series.Mainauthorid, 
       series.Likecount, 
       series.viewcount
 from series join  OrderForSeries on OrderForSeries.SeriesId=Series.id
 join orderforcontent on orderforcontent.OrderForSeriesid=OrderForSeries.id
 group by  OrderForSeries.memberid, orderforseries.seriesid  ,
      Series.Mainauthorid, series.Likecount, series.viewcount 
 order by OrderForSeries.seriesid

but when I change "series.viewcount" in third row to log(series.viewcount) I got error. I consider that this because of GRUOP by query. How can I use log function here?

I am using Microsoft Azure 'import data' But When I use Visual studio it works fine

And this is error :

requestId = 96da06356e5d42b6bf5aede3170f718f errorComponent=Module.
taskStatusCode=400. 
{"Exception":
    { "ErrorId":"InvalidSQLScript",
      "ErrorCode":"0069",
      "ExceptionType":"ModuleException",
      "Message":"Error 0069: SQL query \" 
        select top 75000
          OrderForSeries.memberid, 
          Orderforseries.seriesid ,
          log(count(orderforcontent.id)) as rating,
          Series.Mainauthorid, 
          series.Likecount,
          log(series.viewcount)
        from series 
        join OrderForSeries on OrderForSeries.SeriesId=Series.id
        join orderforcontent on orderforcontent.OrderForSeriesid=OrderForSeries.id
        group by OrderForSeries.memberid, orderforseries.seriesid ,
          Series.Mainauthorid, series.Likecount, series.viewcount
        order by OrderForSeries.seriesid
    " is not correct:
    ??? ?? ??? ??? ??????.
    Please double check your query against your database."
    }
}
Error: Error 0069: 
  SQL query " .... " is not correct:
  ??? ?? ??? ??? ??????.
  Please double check your query against your database. 
Process exited with error code -2 

Answer 1

You should add log function behind GROUP BY . Most of the database systems requires that the attributes or expressions outside the aggregate function needs to be behing GROUP BY and behind SELECT as well

select OrderForSeries.memberid, 
       Orderforseries.seriesid  ,
       log(count(orderforcontent.id)) as rating,
       Series.Mainauthorid, 
       series.Likecount, 
       log(series.viewcount)
 from series join  OrderForSeries on OrderForSeries.SeriesId=Series.id
 join orderforcontent on orderforcontent.OrderForSeriesid=OrderForSeries.id
 group by  OrderForSeries.memberid, 
       Orderforseries.seriesid  ,
       Series.Mainauthorid, 
       Series.Likecount, 
       log(Series.viewcount)
 order by OrderForSeries.seriesid

Answer 2

Not sure what DBMS you're using - MS SQL was able to handle this.

In any case, you've got two options if your DB can't perform operations like log() on grouped-by fields.

Option A - Use a Subquery

Nothing's stopping you from writing

select fieldA, fieldB, log(fieldC)
from
(
    select fieldA, fieldB, fieldC from somewhere
) as subQ

... in other words, use a subquery to generate your raw data, and then use a higher-level query to perform the math you want to do on it.

Option B - change the Group-By to Log() as well.

If the engine doesn't allow you to perform functions on a grouped-by field, you can always add the function into the group by clause.

Select fieldA, log(fieldB)
from somewhere
group by fieldA, log(fieldB)