I wonder if this works: update stock s set s_superceded = true where s.s_updated < (select max(t.s_updated) from stock t where t.s_vin = s.s_vin)
On Thu, May 14, 2009 at 7:27 AM, Gary Stainburn < gary.stainb...@ringways.co.uk> wrote: > I know I should be able to do this but my brain's mashed today > > I have a stock table with > > s_stock_no varchar primary key > s_vin varchar > s_updated timestamp > s_superceded boolean > > It is possible for the same vin to exist on stock if we have sold and then > bought back a vehicle, e.g. as a part exchange. > > Every time a vehicle is inserted/updated the s_updated field is update. > > How can I update the table so that for each s_vin, if a record does not > have > the most recent s_updated value, s_superceded is set to true? > > I can get the most recent value by running: > > select * from (select s_vin, > count(s_updated) as numb, > max(s_updated)::timestamp as latest > from stock > group by s_vin) foo > where numb > 1; > > > but I can't seem to get how I can convert this to an update statement. The > num > > 1 simply removed all vehicles with only one record. > > I seem to think I need an update..... from..... statement > > -- > Gary Stainburn > > This email does not contain private or confidential material as it > may be snooped on by interested government parties for unknown > and undisclosed purposes - Regulation of Investigatory Powers Act, 2000 > > -- > Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-sql >
