"Oliver Elphick" <olly(at)lfix(dot)co(dot)uk> writes:
> You are actually doing a 3-way join, with linia included twice.
> It is implicitly included a second time when a column is referenced
> from it without the alias.
7.1 will provide a NOTICE that's intended to alert people that such
constructs probably don't do what they're expecting:
regression=# select f.f1, int4_tbl.f1 from int4_tbl f;
NOTICE: Adding missing FROM-clause entry for table "int4_tbl"
although I wonder whether this will leave the query author any
less confused :-(.
regards, tom lane