Query takes too long if i include a column in select statement - sql

Question

Below is the query which i need to optimize:
DECLARE #Power VARCHAR(10), #Button VARCHAR(10), #Casing VARCHAR(10), #Screen VARCHAR(10)
SELECT #Power = ActivityId FROM t_Activity WHERE ActivityName = 'PhonePowersUp?'
SELECT #Button = ActivityId FROM t_Activity WHERE ActivityName = 'T/S and Buttons functioning OK?'
SELECT #Casing = ActivityId FROM t_Activity WHERE ActivityName = 'Casing - no major defects?'
SELECT #Screen = ActivityId FROM t_Activity WHERE ActivityName = 'LCD works OK?'
SELECT
HQ.HandsetQuoteId [HandsetQuoteId], SS.Name [quote_status], HQ.QuoteDate [Quote Date], INS.DateInspected [DateInspected], PA.IMEI [IMEI_Quoted],
PA1.IMEI [IMEI_Inspected], INS.Grade [Grade], PB.PackageBoxName [PackageBoxName], CC.Name [ContactChannel], PhnBrd.Name [Brand], PM.ModelName [ModelQuoted],
PM1.ModelName [ModelInspected], U.FirstName [FirstName], U.Surname [Surname], U.Username [Username], UW.WarehouseId [WarehouseId], W.Name [Warehouse Name],
HQA.Value [Original Quote Value], HQ.QuoteValue [Quote Value], INS.InspectionValue [InspectionValue], HQ.AgreedValue [Agreed Value], CUS.FirstName [Store Name],
DATEDIFF(DAY, HQ.QuoteDate, GETDATE()) [Quote Age],
[ST_POWER] = CASE WHEN (CHARINDEX(','+ #Power +',', ','+PAR.Ok+',') > 0) THEN 'YES' WHEN (CHARINDEX(','+ #Power +',', ','+PAR.Fault+',') > 0) THEN 'NO' ELSE NULL END,
[ST_BUTTONS] = CASE WHEN (CHARINDEX(','+ #Button +',', ','+PAR.Ok+',') > 0) THEN 'YES' WHEN (CHARINDEX(','+ #Button +',', ','+PAR.Fault+',') > 0) THEN 'NO' ELSE NULL END,
[ST_CASING] = CASE WHEN (CHARINDEX(','+ #Casing +',', ','+PAR.Ok+',') > 0) THEN 'YES' WHEN (CHARINDEX(','+ #Casing +',', ','+PAR.Fault+',') > 0) THEN 'NO' ELSE NULL END,
[ST_Screen] = CASE WHEN (CHARINDEX(','+ #Screen +',', ','+PAR.Ok+',') > 0) THEN 'YES' WHEN (CHARINDEX(','+ #Screen +',', ','+PAR.Fault+',') > 0) THEN 'NO' ELSE NULL END,
st_deduct = PAR.PercentageDeduction, wt_deduct = MAX(APD.PercentageDeduction)
FROM t_Inspection AS INS
INNER JOIN t_HandsetQuote HQ ON HQ.HandsetQuoteId = INS.HandsetQuoteId
INNER JOIN t_QuoteHeader QH ON QH.QuoteHeaderId = HQ.QuoteHeaderId
INNER JOIN t_Customer CUS ON CUS.CustomerId = QH.CustomerId
INNER JOIN t_ContactChannel CC ON CC.ContactChannelId = CUS.ContactChannelId
INNER JOIN t_PackageBoxHandset PBH ON PBH.HandsetQuoteId = HQ.HandsetQuoteId
INNER JOIN t_PackageBox PB ON PB.PackageBoxId = PBH.PackageBoxId
INNER JOIN t_StockStatus SS ON SS.StockStatusId = HQ.StockStatusId
INNER JOIN t_PhoneAudit PA ON PA.PhoneAuditId = HQ.QuotePhoneAuditId
INNER JOIN t_PhoneModel PM ON PM.PhoneModelId = PA.PhoneModelId AND PA.PhoneAuditId = HQ.QuotePhoneAuditId
INNER JOIN t_PhoneBrand PhnBrd ON PM.PhoneBrandId = PhnBrd.PhoneBrandId
INNER JOIN t_PhoneAudit PA1 ON PA1.PhoneAuditId = HQ.InspectionPhoneAuditId
INNER JOIN t_PhoneModel PM1 ON PM1.PhoneModelId = PA1.PhoneModelId AND PA1.PhoneAuditId = HQ.InspectionPhoneAuditId
INNER JOIN t_PhoneBrand PhnBrd1 ON PM1.PhoneBrandId = PhnBrd1.PhoneBrandId
INNER JOIN t_User U ON INS.InspectorId = U.UserId
INNER JOIN t_UserWarehouse UW ON U.UserId = UW.UserId
INNER JOIN t_Warehouse W ON UW.WarehouseId = W.WarehouseId
LEFT JOIN t_HandsetQuoteAdditionalInfo HQA ON HQ.HandsetQuoteId = HQA.HandsetQuoteId AND HQA.KeyName = 'OriginalQuoteValue'
LEFT JOIN t_PhoneAuditRetail PAR ON PAR.HandsetQuoteId = HQ.HandsetQuoteId
LEFT JOIN t_HandsetQuoteActivity HQA1 ON HQA1.HandsetQuoteId = HQ.HandsetQuoteId AND HQA1.ActivityTestOK = 0 AND HQA1.ActivityStartTime = (
CASE
WHEN ((SELECT Count(1) FROM t_HandsetQuoteActivity WHERE HandsetQuoteId = HQA1.HandsetQuoteId AND ActivityStartTime <= QH.Cache_QuoteAcceptedDate AND ActivityId = HQA1.ActivityId) > 0)
THEN (SELECT Max(ActivityStartTime) FROM t_HandsetQuoteActivity WHERE HandsetQuoteId = HQA1.HandsetQuoteId AND ActivityStartTime <= QH.Cache_QuoteAcceptedDate AND ActivityId = HQA1.ActivityId GROUP BY HandsetQuoteId, ActivityId)
ELSE
(SELECT Min(ActivityStartTime) FROM t_HandsetQuoteActivity WHERE HandsetQuoteId = HQA1.HandsetQuoteId AND ActivityStartTime >= QH.Cache_QuoteAcceptedDate AND ActivityId = HQA1.ActivityId GROUP BY HandsetQuoteId, ActivityId)
END)
LEFT JOIN t_Activity_PercentageDeduction APD ON APD.ActivityId = HQA1.ActivityId AND APD.ContactChannelId = CUS.ContactChannelId AND APD.ContactChannelId = CC.ContactChannelId
WHERE Ins.DateInspected > GETDATE()-90
GROUP BY HQ.HandsetQuoteId, SS.Name, QH.CreatedDate, INS.DateInspected, PA.IMEI, PA1.IMEI, INS.Grade, PB.PackageBoxName, CC.Name, PhnBrd.Name, PM.ModelName, PM1.ModelName,
U.FirstName, U.Surname, U.Username, UW.WarehouseId, W.Name, HQA.Value, HQ.QuoteValue, INS.InspectionValue, HQ.AgreedValue, CUS.Firstname, HQ.QuoteDate, PAR.Ok, PAR.Fault,
PAR.PercentageDeduction
And, after properly debugging it, I came to know that when i remove wt_deduct = MAX(APD.PercentageDeduction) from the select list, the query executes with in less than a minute.
But, however i am not able to figure it out, that whats wrong with the column APD.PercentageDeduction, because when i include it in the select list, my query stucks and becomes too slow and takes 15 minutes to run and excluding it from the select list makes the query to run with in 30 seconds.
Additional Information:
Table -> t_Activity_PercentageDeduction contains only 400 records, column PercentageDeduction is of Decimal datatype.
Please let me know if you want some other information too.

Answer 1

If Im not mistaken you are only joining to that table in order to get that MAX value, and by adding this Max value, you are also having to do all the grouping. So there is actually quite a difference in the queries.
I would suggest using a co-related sub-query to get this piece of data.
remove the left join
LEFT JOIN t_Activity_PercentageDeduction APD ON APD.ActivityId = HQA1.ActivityId AND APD.ContactChannelId = CUS.ContactChannelId AND APD.ContactChannelId = CC.ContactChannelId
and set wt_deduct = to the new co-related sub-query
wt_deduct = (select MAX(PercentageDeduction) from t_Activity_PercentageDeduction
where ActivityId = HQA1.ActivityId
AND ContactChannelId = CUS.ContactChannelId
AND ContactChannelId = CC.ContactChannelId)
And you can remove all the grouping that is no longer required too.