On Fri, Sep 4, 2009 at 9:47 AM, Scott Frankel<leknarf@xxxxxxxxxxx> wrote: > > Hello, > > Is it possible to perform selects in a where clause of a statement? > > Given a statement as follows: > > SELECT foo.foo_id, foo.name > FROM foo, bar > WHERE foo.bar_id = bar.bar_id > AND bar.name = 'martini'; > > I'm looking for a way to recast it so that the select and from clauses refer > to a single table and the join referencing the second table occurs in the > where clause. For example, something like this: > > SELECT foo.foo_id, foo.name > FROM foo > WHERE (SELECT * FROM foo, bar WHERE ...) > foo.bar_id = bar.bar_id > AND bar.name = 'martini'; > > I've explored the "where exists" clause, but it's not supported by the > application toolkit I'm using. AFAIK, I've only got access to where ... where clauses is basically a set of boolean expressions. It's not completely clear how to wrap that inside what you are trying to do. you can do this: WHERE something = (SELECT * FROM foo, bar WHERE ...) or this: WHERE (SELECT count(*) FROM foo, bar WHERE ...) > 0 for example. however, I'd advise dumping the application framework as a long term objective. Another general tactic to try and express what you are looking for in a view and query the view in a more regular way. This is likely your best bet. merlin -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
