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ASP and ADO Gotcha - Duplicate Field Names in a Query

By Leon Platt,

ASP / ADO Gotcha - Duplicate Field Names in a Query

Recently while working on the Sql Server Central site, I ran into a problem that amazed me.  Why was I amazed you ask?  Well I really didn't expect what happened was posible, but sure enough it did.  I was trying to display the results of the votes for a particular book.  The field that contains the value is Books.Rating.  Thus in my display code, I simply typed something like <H3><%=rsart("BookName")%>  Rating: <%=rsart("rating")%></H3>. Much to my dismay, I kept comming up with the wrong rating.  I checked the database table directly and sure enough the value was correct.  After some quality debug time this is what I discovered.  ADO will allow you to use duplicate field names in a query, and when you try to access the value using the fieldname as the index such as in: rsart("rating"), ADO will return the first occurance.  I've got to say, I really would have expected an error but sure enough it works this way!   

strSQL="SELECT P.ArticleID,P.Articletype, P.BookID," & _
   "P.Headline, P.Rating, P.NumberVotes, " & _
   "P.NumberReads, P.PrintableUrl, CONVERT(char(10), " & _
   "P.StartDt,101) AS StartDt, A.FirstName, " & _
   "A.LastName,A.AuthorFolder, A.ColumnistFg, " & _
   "B.Rating,B.BookName,B.ISBN, B.BookPhotoPath FROM P " & _
   "INNER JOIN A ON P.AuthorID = A.AuthorID INNER JOIN B " & _
   "ON P.BookID = B.BookID WHERE (P.ArticleID = 176)" 
rsart.open strSQL,myConn
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