需要格式为yyyy-mm的日期，并且应该分组以获取计数，但是当我给

group by date is says invalid

我找到了这个解决方案

任何人都可以通过提供其他解决方案来帮助我

select 
count(*) as count, 
Convert(char(10), RH.updated_datetime, 105) as date,
SUM( 
  datediff(SECOND, 
       PRI.procedure_performed_datetime ,RH.updated_datetime
  )
)/count(*) as average_reporting_tat 
from 
report R, 
report_history RH, 
study S, 
procedure_runtime_information PRI, 
priorities PP, 
patient P, 
"procedure" PR

where

RH.report_fk=R.pk and RH.pk IN ( 
  select pk from ( 
    select * from report_history where report_fk=r.pk  
  ) as result 
  where old_status_fk IN (21, 27)
) AND R.study_fk = S.pk 
AND S.procedure_runtime_fk = PRI.pk 
AND PRI.procedure_fk = PR.pk 
AND S.priority_fk = PP.pk 
AND PRI.patient_fk = P.pk 
AND RH.updated_datetime >= '2012-05-01' 
AND RH.updated_datetime <= '2013-09-12' 
group by Convert(char(10), RH.updated_datetime, 105)