ranking entries in mysql table

Question

I have a MySQL table with many rows. The table has a popularity column. If I sort by popularity, I can get the rank of each item. Is it possible to retrieve the rank of a partic

Answer 1

There is no way to calculate the order (what you call rank) of something without first sorting the table or storing the rank.

If your table is properly indexed however (index on popularity) it is trivial for the database to sort this so you can get your rank. I'd suggest something like the following:

Select all, including rank

SET @rank := 0;
SELECT t.*, @rank := @rank + 1
FROM table t
ORDER BY t.popularity;

To fetch an item with a specific "id" then you can simply use a subquery as follows:

Select one, including rank

SET @rank := 0;
SELECT * FROM (
  SELECT t.*, @rank := @rank + 1
  FROM table t
  ORDER BY t.popularity
) t2
WHERE t2.id = 1;