Delete records which have more than N entries

I have a table called history, which has three columns. id, value, timestamp

Id is not a primary key, but the pair (id, timestamp) is unique. What I would like to do is delete all the older records for a specific ID that exceed a certain limit. For example if i have these values:

-1,value1,1
-1,value2,开发者_如何学Python2
-1,value3,3
-2,value4,4
-2,value5,5
-2,value6,6

And the limit is 2. After executing the statement i should get something like:

-1,value2,2
-1,value3,3
-2,value4,4
-2,value5,5
-2,value6,6

I think I have it (tried and works for the testcases i had), the answer is:

DELETE  FROM history WHERE id = ?1 AND timestamp NOT in (SELECT sourcetime  FROM    history   WHERE   id =?1 ORDER BY timestamp DESC LIMIT ?2);

DELETE FROM ... WHERE timestamp < ...

Doesn't work ?