Querying for existing set of values

Question

HI,
I have the following scenario. I have one table which has the measure_id,measure_value and date.
For every date, I will be populating the measure_value for every measure_id. 
If the source, doesnt have the value for a day,for a measure_id, I should update it with 0.
If the source gets fresh data for a date, then the related value should get updated(sum of values for that day) or inserted.(incremental)
DATE MeasureID MeasureValue
02/01  1 10
02/01  2 20
02/01  3 30
02/02  1 10
02/02  2 0(no data in source)
02/02  3 30
Can you please give me the best query for this scenario. Any help is appreciated.
Porus

Answer 1

you can try using Merge command.
I have used some sample data in Source and Destination tables.Also i used a measures table with three measure.
Declare @Source Table(Dt Date, MeasureID int, MeasureValue int);
Declare @Destination Table(Dt Date, MeasureID int, MeasureValue int);
Declare @Measure Table (MeasureID int);
Insert into @Measure select 1 union all select 2 union all select 3
Insert into @Source
select '20140201',1,10
union all
select '20140201',2,10
union all
select '20140201',3,10
union all
select '20140202',1,10
union all
select '20140202',3,30
Insert into @Destination
select '20140201',1,0
select * from @Source
select * from @Destination
;With AllMeasures
as
select * from
(SELECT distinct Dt from @Source) A
cross join @Measure
MERGE @Destination AS target
USING
select A.Dt,A.MeasureID,isnull(S.MeasureValue,0) from AllMeasures A
left join @Source S on A.Dt=S.Dt and A.MeasureID=S.MeasureID
) AS source (Dt, MeasureID,MeasureValue)
ON (target.Dt = source.Dt and target.MeasureID = source.MeasureID)
WHEN MATCHED THEN
UPDATE SET MeasureValue = source.MeasureValue
WHEN NOT MATCHED THEN
INSERT (Dt, MeasureID,MeasureValue)
VALUES (source.Dt,source.MeasureID,source.MeasureValue);
select * from @Destination
Vinay Valeti| If you think my suggestion is useful, please rate it as helpful. If it has helped you to resolve the problem, please Mark it as Answer