Find max Date Value for a subqueried list - sql

Question

This is admittedly atrocious code. I'm looking to not only make it work, but make it work well. I would like to get the max date for each Claim Adjustment Type Code.
Current code:
SELECT a.[Current ClaimID], a.[Claim Adjustment Type Code], a.[Claim Effective Date]
FROM #tmp_hic_dupes_list_final_not10 a
join (select a.[Current ClaimID], a.[Claim Adjustment Type Code], a.[Claim Effective Date]
from #tmp_hic_dupes_list_final_not10 as a
where
a.[Claim Adjustment Type Code] in (SELECT a.[Claim Adjustment Type Code]
FROM
#tmp_hic_dupes_list_final_not10 b where
a.[Current HIC #] = b.[Current HIC #] and
a.[Claim Type Code] = b.[Claim Type Code] and
a.[Provider Oscar #] = b.[Provider Oscar #] and
a.[Claim From Date] = b.[Claim From Date] and
a.[Claim Thru Date] = b.[Claim Thru Date] and
a.[Claim Adjustment Type Code] = b.[Claim Adjustment Type Code]
HAVING
COUNT(*) > 1)) b on a.[Current ClaimID] = b.[Current ClaimID]
--WHERE a.[Claim Effective Date] < b.[Claim Effective Date]
group by a.[Current ClaimID], a.[Claim Adjustment Type Code], a.[Claim Effective Date]
having a.[Claim Effective Date] = max(a.[Claim Effective Date])
Current reuslts:
[Current ClaimID] [Claim Adjustment Type Code] [Claim Effective Date]
37274993770 1 2014-02-07 00:00:00.000
37274993771 2 2014-02-07 00:00:00.000
37509451954 1 2014-02-21 00:00:00.000
37509451955 2 2014-02-21 00:00:00.000
38168035124 1 2014-04-04 00:00:00.000
38168035125 2 2014-04-04 00:00:00.000
Expected results:
[Current ClaimID] [Claim Adjustment Type Code] [Claim Effective Date]
38168035124 1 2014-04-04 00:00:00.000
38168035125 2 2014-04-04 00:00:00.000

Answer 1

You could add a RANK() function to the existing code, RANK() each group of type codes by descending date, and then in outer query, pick off just the records with rank = 1
SELECT [Current ClaimID], [Claim Adjustment Type Code], [Claim Effective Date] FROM (
SELECT a.[Current ClaimID], a.[Claim Adjustment Type Code], a.[Claim Effective Date],
RANK() OVER (PARTITION BY a.[Claim Adjustment Type Code] ORDER BY a.[Claim Effective Date] DESC) AS RankClaimTypeByDate
FROM #tmp_hic_dupes_list_final_not10 a
join (select a.[Current ClaimID], a.[Claim Adjustment Type Code], a.[Claim Effective Date]
from #tmp_hic_dupes_list_final_not10 as a
where
a.[Claim Adjustment Type Code] in (SELECT a.[Claim Adjustment Type Code]
FROM
#tmp_hic_dupes_list_final_not10 b where
a.[Current HIC #] = b.[Current HIC #] and
a.[Claim Type Code] = b.[Claim Type Code] and
a.[Provider Oscar #] = b.[Provider Oscar #] and
a.[Claim From Date] = b.[Claim From Date] and
a.[Claim Thru Date] = b.[Claim Thru Date] and
a.[Claim Adjustment Type Code] = b.[Claim Adjustment Type Code]
HAVING
COUNT(*) > 1)) b on a.[Current ClaimID] = b.[Current ClaimID]
--WHERE a.[Claim Effective Date] < b.[Claim Effective Date]
group by a.[Current ClaimID], a.[Claim Adjustment Type Code], a.[Claim Effective Date]
having a.[Claim Effective Date] = max(a.[Claim Effective Date]) ) d WHERE RankClaimTypeByDate = 1 -- Select the 1st ranked record within each [Claim Adjustment Type Code]

Answer 2

One easy way to do this would be to add a where clause that limits the result to those rows for which there does not exist any row with the same Claim Adjustment Type Code and a later Claim Effective Date.
Try adding this to your query:
WHERE NOT EXISTS (
SELECT 1
FROM #tmp_hic_dupes_list_final_not10
WHERE [Claim Adjustment Type Code] = a.[Claim Adjustment Type Code]
AND [Claim Effective Date] > a.[Claim Effective Date]
)
Also, you can probably get rid of the last having clause as it doesn't seem to do anything (but without test data I'm not 100% sure).

Answer 3

A possibility is to join on a subset of the same data you're selecting from that grabs just the MAX([Claim Effective Date]) for each [Claim Adjustment Type Code]. This is more of an additional step on the results of the existing query rather than being a part of it, though (in case that's an option for you):
SELECT a.[Current ClaimID]
,a.[Claim Adjustment Type Code]
,a.[Claim Effective Date]
FROM #tmp_hic_dupes_list_final_not10 a
INNER JOIN (SELECT [ClaimAdjustment Type Code], MAX([Claim Effective Date]) AS MostRecentEffectiveDate
FROM #tmp_hic_dupes_list_final_not10
GROUP BY [ClaimAdjustment Type Code]) AS XYZ
ON a.[Claim Effective Date] = XYZ.MostRecentEffectiveDate
ORDER BY a.[Current ClaimID], a.[ClaimAdjustment Type Code]