Question

This is a sql query that I am using in a page that I am building. It currently runs about 8 seconds and returns 12000 records, which is correct but I am wondering if you could make possible suggestion as to how I could make it faster?

SELECT DISTINCT Advertiser.AdvertiserID, Business.Name, Business.Address1,    Business.Address2, Business.City, Business.State, Business.PostalCode, 
                  Business.Country, Business.Phone, Business.Fax, Business.Email, AdvertiserCategory.CategoryID, AdvertiserCategory.CategoryName AS Category,
                      (SELECT     MAX(PubDate) AS PubDate
                        FROM          NewsPaperAd
                        WHERE      (AdvertiserID = Advertiser.AdvertiserID)
                        GROUP BY AdvertiserID) AS PubDate
FROM Business INNER JOIN
                  Advertiser ON Business.BusinessID = Advertiser.AdvertiserID INNER JOIN
                  Tsheetrecipient ON Advertiser.AdvertiserID = Tsheetrecipient.AdvertiserID LEFT OUTER JOIN
                  AdvertiserCategory INNER JOIN
                  AdvertiserCategoryJoin ON AdvertiserCategory.CategoryID = AdvertiserCategoryJoin.CategoryID ON 
                  Advertiser.AdvertiserID = AdvertiserCategoryJoin.AdvertiserID
WHERE     ((SELECT     MAX(PubDate) AS PubDate
                     FROM         NewsPaperAd AS NewsPaperAd_1
                     WHERE     (AdvertiserID = Advertiser.AdvertiserID)
                     GROUP BY AdvertiserID) IS NOT NULL)
ORDER BY PubDate DESC

I’m really wondering what alternatives there are to the group by clause as this is what is really slowing it down.

Thanks

Answer 1

You could also move the select max date part into your from clause instead of having it in your select and where clauses. Something like:

SELECT DISTINCT Advertiser.AdvertiserID, Business.Name, Business.Address1,    Business.Address2, Business.City, Business.State, Business.PostalCode, 
                  Business.Country, Business.Phone, Business.Fax, Business.Email, AdvertiserCategory.CategoryID, AdvertiserCategory.CategoryName AS Category, pd.PubDate
FROM Business INNER JOIN
                  Advertiser ON Business.BusinessID = Advertiser.AdvertiserID INNER JOIN
                  Tsheetrecipient ON Advertiser.AdvertiserID = Tsheetrecipient.AdvertiserID LEFT OUTER JOIN
                  AdvertiserCategory INNER JOIN
                  AdvertiserCategoryJoin ON AdvertiserCategory.CategoryID = AdvertiserCategoryJoin.CategoryID ON 
                  Advertiser.AdvertiserID = AdvertiserCategoryJoin.AdvertiserID,
                  (SELECT    AdvertiserID, MAX(PubDate) AS PubDate
                     FROM         NewsPaperAd
                     GROUP BY AdvertiserID) AS pd
WHERE    
                pd.AdvertiserID = Advertiser.AdvertiserID AND pd.PubDate IS NOT NULL 
ORDER BY PubDate DESC

Note I didn’t test this query but it should give you a general idea.