Question

I need to left join a few tables in a query where the column names are ambiguous.

ListingCategory_Listings:

ID | ListingCategoryID | ListingID | ..

SiteTree_Live:

ID | ClassName | Title | Content | ..

ListingCategory:

ID | IconID

File:

ID | ClassName | Name | Title | Filename | ..

I have the query:

SELECT * FROM ListingCategory_Listings 
LEFT JOIN Listing ON ListingCategory_Listings.ListingID = Listing.ID 
LEFT JOIN SiteTree_Live ON Listing.ID = SiteTree_Live.ID 
LEFT JOIN ListingCategory ON ListingCategory_Listings.ListingCategoryID = ListingCategory.ID 
LEFT JOIN File ON ListingCategory.IconID = File.ID

Both the listing and listing category data is stored in the SiteTree_Live table, when my records are returned, obviously, the Title, ID, Content and other ambiguous fields are returned under the heading Title, ID, Content.

I need to access both the Listing Title and The Listing Category Title and other specific information. If they had their data stored in different tables I could use select Listing.Title AS lTitle but how can I do something similar in this situation?

Answer 1

You need to alias the columns and give them different labels.
You should always put only the fields you need into the SELECT clause, listing each individually rather than using *.
Good practice also dictates giving each table a short alias.

SELECT L.Title Listing_Title, LC.Title ListingCategory_Title,
       ... all your other columns ...
FROM ListingCategory_Listings LCL
LEFT JOIN Listing L ON LCL.ListingID = L.ID 
LEFT JOIN SiteTree_Live STL ON L.ID = STL.ID 
LEFT JOIN ListingCategory LC ON LCL.ListingCategoryID = LC.ID 
LEFT JOIN File F ON LC.IconID = F.ID