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    <p>You have three choices.</p> <p>The first is to go down the path you are one and try to compare two comma delimited lists. This produces really, really ugly SQL. It does not allow indexes. The basic idea is something like:</p> <pre><code>where find_in_set(substring_index(@list, ',', 1), CarBrands) &gt; 0 or find_in_set(substring_index(substring_index(@list, ',', 2), ',', -1), CarBrands) &gt; 0 or . . . </code></pre> <p>The second is to introduce a new table, which has one row for a user and a favorite whatever. Let's make this general, so there is a column for the user, a column for category ("CarBrand") and a name. Then the query looks something like:</p> <pre><code>from Profile p left outer join Favorites f on p.userId = f.userId and f.Category = 'CarBrand' group by p.userId having sum(f.Name = 'Mercedes') &gt; 0 and sum(f.Name = 'BMW') &gt; 0; </code></pre> <p>The third option is to use full text search and the <code>match</code> function. The documentation is <a href="http://dev.mysql.com/doc/refman/5.5/en/fulltext-boolean.html" rel="nofollow">here</a>.</p> <p>My guess is that a full text index is probably the easiest way for you to do what you want.</p> <p>EDIT:</p> <p>The query about full text index versus option 2. Probably the key question has to do with stop words and short terms. The full text index, for instance, drops words with less than 4 characters (by default, you can change both of these). It also has a list of stop words.</p> <p>My personal inclination would be to use the second option. But the reasons may not be good ones. It uses standard SQL and I'm comfortable with the data structures and queries. So, it gives me more control over the results.</p> <p>In your case, the full text search is probably easier to implement quickly and would very likely be as fast or faster. The full text search also lets you do more complex booleans, such as mixing "AND" and "OR" and doing natural language search to get a relevance value.</p>
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    1. USGordon Linoff
    1. USGordon Linoff
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    1. COGreat infos thanks! i am reading though it and the url you provided. One question already though: option 2 will leave me with a seperate table in which all possible favorite combinations are placed and then save the id of the combination at hand in my original table? Is that also faster / preferable over option 3 or not? Option 3 seems to be easier but not sure if it's the most sensible to do.
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    2. COi will learn soon enough :-) i am switching back and forth between option 2 and 3. 3 seems easier and less tables but i am not quite convinced it is the way to go. Maybe i'm just seeing ghosts! i will do some more reading.
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    3. CO@threeFourOneSixOneThree: i have tried to upvote several answers here but i can't as i do not have enought reputation credits :( and as for accepting an answer: i will do that certainly when i have one that i can go with. Right now i'm considering the answers given and testing things. So, i will accept soon!
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