2009/11/16 Robert Haas <robertmhaas@xxxxxxxxx>: > On Mon, Nov 16, 2009 at 1:31 PM, SebiF <sfeher@xxxxxxxxx> wrote: >> Hi Everyone, >> >> Given a table "Items" with a PK "item1" and "Qty" - a numeric column >> I'd like to define a way in Postgres to insert when item11 doesn't >> exist already in "Items" and update the Qty by adding the new quantity >> to the existent when the item11 exists. What is a good approach and >> where should I be looking for details. Thanks. >> >> Sebastian > > This is not a -hackers question; please use pgsql-general instead. > > Also see example 38-2 here: > http://www.postgresql.org/docs/current/static/plpgsql-control-structures.html > > ...Robert > You could try something like the following: CREATE FUNCTION update_items(item_value TEXT, qty_value INTEGER) RETURNS BOOL AS $$ DECLARE item_rec RECORD; BEGIN SELECT INTO item_rec * FROM items WHERE item = item_value; IF item_rec.item IS NULL THEN INSERT INTO items (item, qty) VALUES (item_value, qty_value); RAISE NOTICE 'added'; RETURN true; ELSE UPDATE items SET qty = qty + qty_value WHERE item = item_value; RAISE NOTICE 'updated'; RETURN true; END IF; END; $$ LANGUAGE plpgsql Then use: SELECT update_items('monkey',9); You could probably also create an updateable view with a rule applied or something. Thom -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
