Question

i’m trying fulltext search with tags but it doesn’t works properly for me chek attached image please

The query is:

 SELECT *, 
         MATCH(tags) AGAINST ('tag3 tag6 tag4') AS score 
    FROM items
ORDER BY score DESC

why does the score is not ordering in the right order fields? if you check the second row has all the tags i searched while the first field does not have tag3 keyword .

i mean id fields order should be : 5,1,2 .. etc and NOT 1,5,2..etc

where is my mistake?

then i would like to search first in tags field then if no results i would like to search the same keyword as FULLTEXT inside description field, so users will search both in tags and description if tags does not match , is it possible in the same query or i need two separated queries?

Answer 1

In this document http://dev.mysql.com/doc/refman/5.0/en/fulltext-natural-language.html it says “For very small tables, word distribution does not adequately reflect their semantic value, and this model may sometimes produce bizarre results.”

If your items table is small — a sample table, for example — you are probably hitting this problem and getting a “bizarre” result.

You may wish to try this query IN BOOLEAN MODE to see if your results match your prediction. Try this.

    SELECT *, 
           MATCH(tags) AGAINST ('tag3 tag6 tag4' IN BOOLEAN MODE) AS score 
      FROM items
  ORDER BY score DESC

The Boolean mode disables the word-distribution ranking. Notice that you should understand the difference between natural-language and Boolean modes, and once you have a decently sized table, make a smart choice about which one to use. If you’re searching for the kind of tags that blogs have in them, Boolean may be the way to go.