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POSubquery returns multiple rows issue
 

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  1. POSubquery returns multiple rows issue
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    <p>Once again a question about mysql with my small database to practise with:</p> <p>I got the tables as followed:</p> <pre><code>Songs Link Tags ======= ===== ======= Sid Sid Tid Songname Tid Tagname </code></pre> <p>Now what I am trying to do is once i query (or search for) a song with entering some tags, to display how many tags that song has to create a match percentage.</p> <p>Thanks to the awesome stackoverflow community i got the query</p> <pre><code>SELECT s.Sid, s.Songname FROM Songs s JOIN Link l ON ( l.Sid = s.Sid ) JOIN Tags t ON ( t.Tid = s.Tid ) WHERE t.Tagname IN ( 'X', 'Y' ) GROUP BY s.Sid, s.Songname HAVING COUNT(1) = 2 </code></pre> <p>Which searches for songs that match exactly these 2 tags. <br/> Suppose now you've got this song A which has tag G, X, Y, and Z. <br/> The query finds this song because it has X and Y in it. However the song got 2 others, thus I want to create (with php) a match % showing 50% for this one.<br/><br/> I don't have any trouble with the php part, but i cant figure out a query to get all songs that match these tags along with their total amount of tags in one result set.</p> <p>Cheers!</p> <h2>Edit1:</h2> <p><hr/> I noticed that most of the answers show what I've already tried. So i'll make another more deep example: <br/> Suppose you've got the following 4 songs: <br/><br/> A with tags A, B, X and Y <br/> B with tags A, B, C, D, E, X, Y <br/> C with tags A, B, C, D, F, X <br/> D with tags X and Y <br/><br/></p> <p>Now the query for searching songs with tags X and Y is enterred. I want the following output: <br/></p> <pre><code>TotalNumberOfTags: Song: 4 A 7 B 2 D </code></pre> <p>C didn't have X AND Y so he falls out.</p> <h2>Edit2:</h2> <p><hr/> To illustrate i want to use the query</p> <pre><code>SELECT COUNT(t.Tagname) FROM FROM Songs s JOIN Link l ON ( l.Sid = s.Sid ) JOIN Tags t ON ( t.Tid = s.Tid ) WHERE s.Songname="A" </code></pre> <p>on the whole returning set of songnames caused by the queries above, in one query to use ORDER BY COUNT(t.Tagname) ASC on the set.</p>
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