Question

Lets just put it at its simplest, a table with two fields: ‘item_id’ & ‘times_seen’.

| item_id | times_seen |
----------+-------------
|   1001  |     48     |
|   1002  |     25     |
|   1003  |      1     |
|   1004  |     12     |
|   1005  |     96     |
|   1006  |     35     |

I’m trying to find a way to randomly select a row, but give preference to items that haven’t been selected much before.

(obviously, a second query would be sent to increment the ‘times-seen’ field after it has been selected)

Although my current “project” is a php/mysql one, I’d like language agnostic solutions if possible. I’d much rather have a math based solution that could be adapted elsewhere. I’m not opposed to a php solution though. I’d just like to be able to understand how the code works rather than just copy and paste it.

Answer 1

How about a SQL solution:

select * from item order by times_seen + Rand()*100 limit 1;

How much you multiply random with (Its a value between 0 and 1) depends on how much randomness you want..

Edit: http://dev.mysql.com/doc/refman/5.0/en/mathematical-functions.html#function_rand