Connecting multiple queries and passing criteria from one query to another - sql

Question

I am trying to put together a query that will basically run another query on each return.
My current query puts together important info for each client, such as how long an average groom takes and the description of the type of haircut they get:
SELECT Query11.petId AS PetID,
Query11.petName AS PetName,
dbo_Customer.cstLName AS LastName,
Query11.lstValue AS Breed,
qryFindsPetAvgApptTime.TotalAppts,
dbo_vwPetGroom.pgrName AS GroomStyle,
dbo_ListValues.lstValue AS Haircut,
ROUND([AvgPTime]) AS AvgPrep,
ROUND([AvgBTime]) AS AvgBath,
ROUND([AvgDTime]) AS AvgDry,
ROUND([AvgGTime]) AS AvgGroom,
[AvgPrep] + [AvgBath] + [AvgDry] + [AvgGroom] AS AvgMinutes,
qryFindsPetAvgApptTime.AvgHours
FROM((Query11
LEFT JOIN qryFindsPetAvgApptTime ON Query11.petId = qryFindsPetAvgApptTime.PetID)
LEFT JOIN dbo_Customer ON Query11.petCustId = dbo_Customer.cstId)
LEFT JOIN (dbo_vwPetGroom
LEFT JOIN dbo_ListValues ON dbo_vwPetGroom.pgrLengthHairBodyLid = dbo_ListValues.lstId)
ON Query11.petId = dbo_vwPetGroom.pgrPetId;
I want to add in the average length between grooming appts to the above query info. Right now that is done in 2 seperate queries.
The first one pulls days between appts:
SELECT tblTimeLog.PetID,
tblTimeLog.PetName,
[ApptDate] - (SELECT MAX(T.ApptDate)
FROM tblTimeLog T
WHERE T.PetID = tblTimeLog.PetID
AND T.ApptDate < tblTimeLog.ApptDate) AS Diff,
tblTimeLog.ApptDate
FROM tblTimeLog
WHERE (((tblTimeLog.PetID) = [Enter PetID]))
ORDER BY tblTimeLog.ApptDate;
And then averaged out with this:
SELECT qryTimeLogDiffs.PetID,
qryTimeLogDiffs.PetName,
AVG(qryTimeLogDiffs.Diff) AS AvgOfDiff
FROM qryTimeLogDiffs
GROUP BY qryTimeLogDiffs.PetID,
qryTimeLogDiffs.PetName;
Is there a way to pass the PetID criteria from each return into the second query so it adds the average span between appts to the info in the first query??

Answer 1

Consider refactoring your second query to avoid the taxing correlated aggregate subquery. One approach involves first running an aggregate query based on a self join to return last appointment date for each PetID.
Even better, turn this query into an action query to populate a temporary table either with make-table query as shown below using INTO or regularly cleaning out a persistent table via delete and insert-select query:
SELECT curr.PetID,
curr.PetName,
curr.ApptDate,
MAX(prev.[AppDate]) AS MaxPrevDate
INTO lastApptTimeLog
FROM tblTimeLog AS curr
INNER JOIN tblTimeLog AS prev
ON curr.PetID = prev.PetID
WHERE prev.ApptDate < curr.AppDate
GROUP BY curr.PetID,
curr.PetName,
curr.ApptDate;
Then, base third aggregate query on this temp table and run the difference calculation. Finally, incorporate this query into first query.
SELECT PetID,
PetName,
AVG(ApptDate - MaxPrevDate) AS AvgOfDiff
FROM lastApptTimeLog
GROUP BY PetID,
PetName;