Louis-David Mitterrand <vindex+lists-pgsql-...@apartia.org> wrote: > Here is my schema:
> cruise_line -> ship(id_line) -> cruise_type(id_ship) -> cruise(id_cruise_type) > -> price(id_cruise, id_currency) <- currency (USD,GBP,EUR,CAD) > (a 'cruise' is a 'cruise_type' + a date) > I am trying to display a count of cruise's for each ship and each > currency even if that count is 0. > But I am having trouble building the query, as some 'cruise's might not > (yet) have a 'price' in all currencies and so no link to 'currency'. You're probably looking for a "LEFT JOIN". Tim -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
