Question

I have a simple table “t1” that contains:

word VARCHAR(16)
id INT
importance SMALLINT

word and id are unique together, but neither is unique alone.

I added a UNIQUE INDEX(word, id)

My query looks something like this:

SELECT id FROM t1 WHERE word = "something" ORDER BY importance DESC

But it takes 0.0002 seconds to execute say:

SELECT id FROM t1 WHERE word = "something"

But takes as much as 0.15s to execute the ORDER BY importance DESC.

My question is, how can I index/reorder my table so it’s organized firstly by word, then by importance without having to do the sorting on the fly?

Can I just reorder the static data so it’s sorted by word, importance DESC by default?

Answer 1

To speed up your query, add an index on (word, importance DESC, id).

You can have more than one index on a table so you don’t need to remove your existing index if you don’t want to.