Re: Check for existence of index

David Rysdam <drysdam(at)ll(dot)mit(dot)edu> writes:
> Why can't I have the same index name be on
> different tables?

You can ... if they are in different schemas. Indexes and tables share
the same namespace, ie, they must be unique within a schema.

As for your original question, you probably want something like

SELECT ... FROM pg_class c, pg_namespace n WHERE c.relnamespace = n.oid
AND relname = 'indexname' AND nspname = 'schemaname' AND relkind = 'i';

If you actually want to verify that this index is on a specific table,
you'll need a more complicated join involving pg_index and a second
scan of pg_class. See
http://www.postgresql.org/docs/8.0/static/catalogs.html

regards, tom lane