How to write mysql query to search database? - mysql

Question

I'm own a wallpaper website and I'm trying to write a search feature that will search the database for the terms the user is searching for. I have 2 fields in the database I'm searching against TAGS and NAME
The current way I'm doing it is I take the search term divide it up into multiple words and then search the database using those terms. So if a user searches for "New York" my query will look like this
SELECT * FROM wallpapers
WHERE tags LIKE '%New%' OR name LIKE '%new%'
or tags LIKE '%York%' OR name LIKE '%York%'
The issue with that of course is that anything with the term new in it will be pulled up also like say "new car" etc. If I replace the query above with the following code then it's too vague and only like 2 wallpapers will show up
SELECT * FROM wallpapers
WHERE tags LIKE '%New York%' OR name LIKE '%New York%'
Does anyone have a better way to write a search query?

Answer 1

Looks like you want to introduce the concept of relevance.
Try:
select * from (
SELECT 1 as relevance, * FROM wallpapers
WHERE tags LIKE '%New York%' OR name LIKE '%New York%'
union
select 10 as relevance, * FROM wallpapers
WHERE (tags LIKE '%New%' OR name LIKE '%new%')
and (tags LIKE '%York%' OR name LIKE '%York%')
union
select 100 as relevance, * FROM wallpapers
WHERE tags LIKE '%New%' OR name LIKE '%new%'
union
select 100 as relevance, * FROM wallpapers
WHERE tags LIKE '%York%' OR name LIKE '%York%'
)
order by relevance asc
By the way, this will perform very, very poorly if your database grows too large - you want to be formatting your columns consistently so they're all upper case (or all lower case), and you want to avoid wildcards in your where clauses if you possibly can.
Once this becomes a problem, look at full text searching.

Answer 2

Perhaps this is a really dumb question, but could be following possibly what you want?
SELECT * FROM wallpapers
WHERE ( tags LIKE '%New%' OR name LIKE '%new%' )
and ( tags LIKE '%York%' OR name LIKE '%York%' )
This searches for wallpapers which must have both words but anywhere.
Warning Beware of SQL injection this way, when searching for "words" like new'york or new%york. Perhaps the most easy way is to treat all nonalpha/nonnumeric characters as spaces when splitting, such that new#york and similar becomes new and york.
Notes about searching:
Searching this way in databases is plain overkill (full table scan). As long as you only have a few wallpapers this is not a bigger problem. Nearly all current cheap hardware should be able to search through a million wallpapers within a second or so, as long as the database fits into memory.
However with bigger sites where the tags and name information exceeds available RAM, you certainly get a problem. Then it is time to try some other way to search. However what to do heavily depends on the expected use pattern, so to answer that more information is needed.

Answer 3

You can use your first query to do a first selection and after that your can rank the results : a wallpaper with both keywords "New" and "York" will be ranked higher than a wallpaper with only one of the keywords.
If the second query only returns 2 wallpaper, can you put some example of the tags/name of the wallpaper not returned by the query but that you would like to have ?
Is it a problem of uppercase letters ? Spaces ?

Answer 4

I believe you may benefit from Full text indexes. Read up on mysql full text search. You will need to be using MyISAM engine for your tables.
http://dev.mysql.com/doc/refman/5.0/en/fulltext-search.html