sql - sqlite equivalent of row_number() over ( partition by ...?

Question

I'd like to know if it's possible to do the following using a single sqlite statement:

My table looks something like this:

|AnId|UserId|SomeDate|SomeData|
|123 |A     |1/1/2010|aadsljvs|
| 87 |A     |2/9/2010|asda fas|
|193 |A     |2/4/2010|aadsljvs|
|927 |A     |7/3/2010|aadsasdf|
|816 |B     |1/1/2010|aa32973v|
|109 |B     |7/5/2010|aaasfd10|
| 39 |B     |1/3/2010|66699327|
...

Each row has a unique id, a user id, a datetime value, and some other data.

I'd like to delete records so I keep the latest 10 records per user, based on SomeDate.

In sql server I'd use something like this:

delete d
from data d
inner join (
    select UserId
        ,  AnId
        ,  row_number() over ( partition by UserId order by SomeDate desc ) 
              as RowNum
    from data 
) ranked on d.AnId = ranked.AnId
where ranked.RowNum > 10

Is there a way to do this in sqlite? The edge case where there are several records with the same SomeDate isn't a particular worry, e.g. if I keep all those records that'd be fine.

Answer 1

I know this question is old, but the following SQLite statement will do what Rory was originally asking for in one statement - Delete all records for a given UserId that are not the 10 most recent records for that UserId (based on SomeDate).

DELETE FROM data
WHERE AnId IN (SELECT AnId
               FROM data AS d
               WHERE d.UserId = data.UserId
               ORDER BY SomeDate DESC
               LIMIT -1 OFFSET 10)