How do I delete a fixed number of rows with sorting in PostgreSQL?

Question

I\'m trying to port some old MySQL queries to PostgreSQL, but I\'m having trouble with this one:

DELETE FROM logtable ORDER BY timestamp LIMIT 10;
         


        

Answer 1

You could try using the ctid:

DELETE FROM logtable
WHERE ctid IN (
    SELECT ctid
    FROM logtable
    ORDER BY timestamp
    LIMIT 10
)

The ctid is:

The physical location of the row version within its table. Note that although the ctid can be used to locate the row version very quickly, a row's ctid will change if it is updated or moved by VACUUM FULL. Therefore ctid is useless as a long-term row identifier.

There's also oid but that only exists if you specifically ask for it when you create the table.