I've got some data of two objects and I want to retrieve the last row of both the objects, preferably in one query.
CREATE TABLE data ( pid serial NOT NULL, dt timestamp without time zone, object_id integer, info_1 numeric(10,8), speed numeric, CONSTRAINT dat_pid PRIMARY KEY (pid) )
1, 2014-04-29 12:02:56, 8, .... 2, 2014-04-29 12:02:10, 8, .... 3, 2014-04-29 12:01:02, 8, .... 5, 2014-04-29 12:01:32, 6, .... .....
I want a row per unique object ID, each row being the newest one available. I tried to achieve it by using this query, but it wants pid to be in the group by clause. But I don't want to group by the PID, but at the tracker id....
SELECT * FROM data GROUP BY object_id