How can I return a row if its ID is not found in another table?

Question

I have a 2 tables in a MS SQL 2008 Database, Listings and ListingType, I want to create a select statement that will give me all rows from Listing that do not have their ListingID in the ListingType table.

I'm very confused about how to even start this statement.

Example SQL Statement - Does a lot more than what I explained, but you should be able to get what I'm asking from it.

SELECT     Listing.Title, Listing.MLS, COALESCE (Pictures.PictureTH, '../default_th.jpg') AS PictureTH, COALESCE (Pictures.Picture, '../default.jpg') AS Picture, Listing.ID, 
                      Listing.Description, Listing.Lot_Size, Listing.Building_Size, Listing.Bathrooms, Listing.Bedrooms, Listing.Address1, Listing.Address2, 
                      Listing.City, Locations.Abbrev, Listing.Zip_Code, Listing.Price, Listing.Year_Built, ListingTypeMatrix.ListingTypeID
FROM         Listing INNER JOIN
                      Locations ON Listing.State = Locations.LocationID LEFT OUTER JOIN
                      ListingTypeMatrix ON Listing.ID = ListingTypeMatrix.ListingID LEFT OUTER JOIN
                      Pictures ON Listing.ID = Pictures.ListingID
WHERE     (ListingTypeMatrix.ListingTypeID = '4') AND 
          ((Pictures.ID IS NULL) OR (Pictures.ID =
                          (SELECT     MIN(ID)
                            FROM          Pictures
                            WHERE      (ListingID = Listing.ID))))

ListingTypeMatrix.ListingTypeID = '4' is the part I dont know what to change it to, because there will not be a record for it.

Solution 1

Using NOT EXISTS

SELECT t.*
  FROM LISTING t
 WHERE NOT EXISTS(SELECT NULL
                    FROM LISTINGTYPE lt
                   WHERE lt.listingid = t.listingid)

Using NOT IN

SELECT t.*
  FROM LISTING t
 WHERE t.listingid NOT IN (SELECT lt.listingid
                             FROM LISTINGTYPE lt)

Using LEFT JOIN/IS NULL

   SELECT t.*
     FROM LISTING t
LEFT JOIN LISTINGTYPE lt ON lt.listingid = t.listingid
    WHERE lt.listingid IS NULL

Summary

Quote:

In SQL Server, NOT EXISTS and NOT IN predicates are the best way to search for missing values, as long as both columns in question are NOT NULL. They produce the safe efficient plans with some kind of an Anti Join.

LEFT JOIN / IS NULL is less efficient, since it makes no attempt to skip the already matched values in the right table, returning all results and filtering them out instead.

Solution 2

   SELECT *
     FROM Listing l
LEFT JOIN ListingType t ON l.ID = t.ListingID
    WHERE t.ListingID IS NULL

Solution 3

The following SQL will return all Listing records without a corresponding ListingType record

SELECT *
FROM Listing
LEFT JOIN ListingType ON Listing.ID = ListingType.ListingID
WHERE ListingType.ID IS NULL

Solution 4

Assuming that the rest of your SQL is corret, just add a null check on ListingTypeID:

SELECT Listing.Title, Listing.MLS, COALESCE (Pictures.PictureTH, '../default_th.jpg') AS PictureTH, COALESCE (Pictures.Picture, '../default.jpg') AS Picture, Listing.ID, Listing.Description, Listing.Lot_Size, Listing.Building_Size, Listing.Bathrooms, Listing.Bedrooms, Listing.Address1, Listing.Address2, Listing.City, Locations.Abbrev, Listing.Zip_Code, Listing.Price, Listing.Year_Built, ListingTypeMatrix.ListingTypeID 
FROM Listing 
INNER JOIN Locations ON Listing.State = Locations.LocationID 
LEFT OUTER JOIN ListingTypeMatrix ON Listing.ID = ListingTypeMatrix.ListingID 
LEFT OUTER JOIN  Pictures ON Listing.ID = Pictures.ListingID 
WHERE (ListingTypeMatrix.ListingTypeID = '4' OR ListingTypeMatrix.ListingTypeID IS NULL) AND  
          ((Pictures.ID IS NULL) OR (Pictures.ID = 
                          (SELECT     MIN(ID) 
                            FROM          Pictures 
                            WHERE      (ListingID = Listing.ID)))) 

Solution 5

I think what you may want to move the ListingTypeMatrix.ListingTypeID = '4' to the ON clause for ListingTypeMatrix OUTER JOIN. The clause would look like this

LEFT OUTER JOIN ListingTypeMatrix ON Listing.ID = ListingTypeMatrix.ListingID
       AND ListingTypeMatrix.ListingTypeID = '4'

And, you would remove ListingTypeMatrix.ListingTypeID = '4' AND from the WHERE clause.

This change will only return rows from ListingTypeMatrix that = 4, and join the results to the rest of the query. The LEFT OUTER JOIN indicates that rows from Listing and Locations will not be excluded if rows do not appear in ListingTypeMatrix.

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Comments

[Wanjia]

not excists or not in seems to work better than left join is null