Is there a way to optimize this query - mysql

Question

I have written a query but it's taking a lot of time. I want to know if there exists any solution to optimize it without making a temp table in MYSQL. Is there a way to optimize the subquery part since AccessLog2019 is huge so it's taking forever)
Here is my query
SELECT distinct l.ListingID,l.City,l.ListingStatus,l.Price,l.Bedrooms,l.FullBathrooms, gc.Latitude,gc.Longitude , count(distinct s.AccessLogID) AS access_count, s.LBID , lb.CurrentListingID
from lockbox.Listings l
JOIN lockbox.GeoCoordinates gc ON l.ListingID = gc.ID
LEFT JOIN lockbox.LockBox lb ON l.ListingID = lb.CurrentListingID
LEFT JOIN
(SELECT * FROM lockbox.AccessLog2019 ac where ac.AccessType not in('1DayCodeGen','BluCodeGen','SmartMACGen') AND DATEDIFF(NOW(), ac.UTCAccessedDT ) < 1 ) s
ON lb.LBID = s.LBID
WHERE l.AssocID = 'AS00000000CC' AND (gc.Confidence <> '5 - Unmatchable' OR gc.Confidence IS NULL OR gc.Confidence = ' ')
group BY l.ListingID
Thanks

Answer 1

If you can avoid the outer group by, that is a big win. I am thinking:
SELECT l.ListingID, l.City, l.ListingStatus, l.Price, l.Bedrooms, l.FullBathrooms,
gc.Latitude, gc.Longitude,
(select count(*)
from lockbox.LockBox lb join
lockbox.AccessLog2019 ac
on lb.LBID = ac.LBID
where l.ListingID = lb.CurrentListingID and
ac.AccessType not in ('1DayCodeGen', 'BluCodeGen', 'SmartMACGen') and
DATEDIFF(NOW(), ac.UTCAccessedDT) < 1
) as cnt
from lockbox.Listings l JOIN
lockbox.GeoCoordinates gc
ON l.ListingID = gc.ID
WHERE l.AssocID = 'AS00000000CC' AND
(gc.Confidence <> '5 - Unmatchable' OR
gc.Confidence IS NULL OR
gc.Confidence = ' '
)
Note: This does not select s.LBID or lb.CurrentListingID because these don't make sense in your query. If I understand correctly, these could have different values on different rows.

Answer 2

You could try breaking out the subquery to the JOIN clause.
It might give a hint to the optimizer that it can use the LBID field first, and then test the AccessType later (in case the optimizer doesn't figure that out when you have the sub-select).
SELECT distinct l.ListingID,l.City,l.ListingStatus,l.Price,l.Bedrooms,l.FullBathrooms, gc.Latitude,gc.Longitude , count(distinct s.AccessLogID) AS access_count, s.LBID , lb.CurrentListingID
from lockbox.Listings l
JOIN lockbox.GeoCoordinates gc ON l.ListingID = gc.ID
LEFT JOIN lockbox.LockBox lb ON l.ListingID = lb.CurrentListingID
LEFT JOIN AccessLog2019 s
ON lb.LBID = s.LBID
AND s.AccessType not in('1DayCodeGen','BluCodeGen','SmartMACGen')
AND DATEDIFF(NOW(), s.UTCAccessedDT ) < 1
WHERE l.AssocID = 'AS00000000CC' AND (gc.Confidence <> '5 - Unmatchable' OR gc.Confidence IS NULL OR gc.Confidence = ' ')
group BY l.ListingID
Note that this is one of those cases where conditions in the JOIN clause gives different behavior than using a WHERE clause. If you just had lb.LBID = s.LBID and then had the conditions I wrote in the WHERE of the outer query the results would be different. They would exclude the records matching lb.LBID = s.LBID. But in the JOIN clause, it is part of the conditions of the outer join.

Answer 3

SELECT * --> Select only the columns needed.
SELECT DISTINCT ... GROUP BY -- Do one or the other, not both.
Need composite INDEX(AssocID, ListingID) (in that order)
DATEDIFF(NOW(), ac.UTCAccessedDT ) < 1 --> ac.UTCAccessedDT > NOW() - INTERVAL 1 DAY (or whatever your intent was. Then add INDEX(UTCAccessedDT)
OR is hard to optimize; consider cleansing the data so that Confidence does not have 3 values that mean the same thing.