请问一条sql语句的优化
语句如下
请高人 帮忙优化下
declare @c_id intSEt @c_id =19select top 10000 * into #temp from [CarVehicleData_tbl] where c_id=@c_id order by [CSN_UpdateTime] descselect max([CSN_ID]) as [CSN_ID], c_id, [CSN_Part],[CSN_Type], max([CSN_UpdateTime]) as [CSN_UpdateTime] into #temp2from #tempgroup by c_id ,[CSN_Part],[CSN_Type]select *,(select top 1 [CSN_DataOriginal] from [CarVehicleData_tbl] a where b.csn_updateTime=a.csn_updateTime order by csn_updateTime desc ) as [CSN_DataOriginal] into #temp3 from #temp2 bselect c_id,[CSN_Part],data1 =max( case csn_type when 0 then [CSN_DataOriginal] end ),data2=max( case csn_type when 1 then [CSN_DataOriginal] end ) into #temp4 from #temp3group by c_id,[CSN_Part]select *,null as a ,null as b from #temp3drop table #tempdrop table #temp2drop table #temp3drop table #temp4
declare @c_id intSEt @c_id =19select top 10000 * into #temp from [CarVehicleData_tbl] where c_id=@c_id order by [CSN_UpdateTime] DESCCREATE INDEX IX_#temp_ALL ON #temp(c_id,[CSN_Part],csn_type,csn_updateTime,CSN_DataOriginal) INCLUDE ([CSN_DataOriginal])select a.c_id, a.[CSN_Part], data1=MAX(CASE WHEN a.[CSN_Type]=0 THEN b.csn_updateTime IS NOT NULL THEN a.CSN_DataOriginal end), data2=MAX(CASE WHEN a.[CSN_Type]=1 THEN b.csn_updateTime IS NOT NULL THEN a.CSN_DataOriginal end
