Re: SQL Join query

* Thus wrote Lenar Lhmus: > Mattias Thorslund wrote: > > > Though, (regardless of SQL database platform) in a case like this, it > > MAY be both more straightforward and efficient to use two separate > > queries for the pictures and comments, given the one-to-many cardinality > > between them. The above statement causes redundant data to be returned > > - it duplicates the pics record for each new comment. If there are many > > large columns in the pics table and many comments to each record there's > > a lot of redundant data in a query like that. > > No, I think you are wrong. There was GROUP BY pics.id so it won't return > duplicate data. And probable overhead is eliminated too I think - DBserver > will optimize and will join data from pic_comments only once for each > unique pics.id. The results will be something like: id submitter count pic_id comment 1 joe 4 1 comment1 1 joe 4 1 comment2 1 joe 4 1 comment3 1 joe 4 1 comment4 2 john 0 2 NULL 3 jim 5 3 comment6 3 jim 5 3 comment7 3 jim 5 3 comment8 3 jim 5 3 comment9 3 jim 5 3 comment10 Curt -- First, let me assure you that this is not one of those shady pyramid schemes you've been hearing about. No, sir. Our model is the trapezoid!