mysql like% query is slow with full-text index
I'm using a simple mysql LIKE query like this:
SELECT * FROM myTable WHERE field LIKE 'aaa%' ORDER BY field2
I have a full-text index on "field", and still it is very slow. I understood there is an option to use match. What is the difference? How? What is the best approach for my usage? Notice I'm using the "%" for everything that starts with "aaa"
UPDATE:
I've ended up using something like this:
SELECT
*, MATCH (name) AGAINST ('a*' IN BOOLEAN MODE) AS SCORE
FROM
users
WHERE
MATCH (name) AGAINST ('a*' IN BOOLEAN MODE)
ORDER BY SCORE, popularity DESC LIMIT 4
One thing I would like to change, is not due the order by firstly by SCORE and then by my field po开发者_运维问答pularity, and instead order by a simple weight function, something like 0.5*SCORE + 0.5*popularity. How?
LIKE
does not use the full-text index. To make use of the fulltext index, you have to use match (as you said):
SELECT *
FROM myTable
WHERE MATCH(field) AGAINST ('aaa*' IN BOOLEAN MODE)
ORDER BY field2
The MySQL Manual has a extensive Chapter on Full-Text Search Functions.
The above answer is correct but I want to add that if you are just going to filter by a field starting with like this
WHERE field LIKE 'aaa%' ORDER BY field2
then a normal index would work.
If you want to search by contains (i.e. field like '%aaa%'
), then you will have to use a full-text index as mentioned above.
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