Re: simple (?) join
От | Claus Guttesen |
---|---|
Тема | Re: simple (?) join |
Дата | |
Msg-id | b41c75520909251536p605e4838q8299a7a00d440982@mail.gmail.com обсуждение исходный текст |
Ответ на | simple (?) join (Gary Stainburn <gary.stainburn@ringways.co.uk>) |
Список | pgsql-sql |
> I have two tables > > create table orders ( > o_id serial primary key > ... > ); > > create table orders_log ( > ol_id serial primary key, > o_id int4 not null references orders(o_id), > ol_timestamp timestamp, > ol_user, > ); > > How can I select all from orders and the last (latest) entry from the > orders_log? Maby this will work? Get the unique o_id from the table orders and do a group by in a subselect, and then select the other fields from the same table, ie: select o_od, max(o_field1), max(o_field2) ... from orders where o_id in (select o_id from orders group by o_id) group by o_id order by o_id; This off course assumes that o_id is a serial (and thus that timestamp will always be higher etc.). -- regards Claus When lenity and cruelty play for a kingdom, the gentler gamester is the soonest winner. Shakespeare
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