Question

Once again a question about mysql with my small database to practise with:

I got the tables as followed:

Songs       Link        Tags
=======     =====       =======
Sid          Sid        Tid
Songname     Tid        Tagname

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.

Thanks to the awesome stackoverflow community i got the query

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

Which searches for songs that match exactly these 2 tags.
Suppose now you’ve got this song A which has tag G, X, Y, and Z.
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.

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.

Cheers!

Edit1:

---

I noticed that most of the answers show what I’ve already tried. So i’ll make another more deep example:
Suppose you’ve got the following 4 songs:

A with tags A, B, X and Y
B with tags A, B, C, D, E, X, Y
C with tags A, B, C, D, F, X
D with tags X and Y

Now the query for searching songs with tags X and Y is enterred. I want the following output:

TotalNumberOfTags:    Song:
4                      A
7                      B
2                      D

C didn’t have X AND Y so he falls out.

Edit2:

---

To illustrate i want to use the query

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"

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.

Answer 1

The answer i found is a work around but it works.
I create a temporary table like this

CREATE TEMPORARY TABLE numberoftags ( songname VARCHAR(50) NOT NULL, numberoftags INT);

which i fill with the 2 separate queries i displayed in my question.
Then with with a simple query

SELECT * FROM numberoftags ORDER BY numberoftags DESC

I receive all songs with their total number of tags, which i display one by one.
After i close the connection in php this temporary table automatically get’s removed, so no hassling about that.