PG Bug reporting form <noreply@postgresql.org> writes:
> During refactoring our application I got a bogus syntax error when adding a
> simple where-clause to a working query.
My guess is that this:
> ('0'||split_part(split_part(nline,'(',2),')',1))::smallint as nlen
sometimes produces a string that fails to cast to smallint, which you
accidentally don't notice because it never gets evaluated for troublesome
values of nline --- until you add the "nlen > 0" condition. There isn't
anything in your query that prevents that from being evaluated fairly
early.
This isn't a bug, or at least you have provided no data that would
motivate (or indeed allow) anyone else to poke into it more closely.
regards, tom lane