Tom Lane writes:
> Not only for historical reasons: there are cases where it allows you
> to do things you couldn't easily do otherwise.  An example is deleting
> using a join:
>
>     DELETE FROM target WHERE field1 = source.field2
Wow, that seems pretty bogus to me.
> Bruce had actually put in some code to emit warnings, but Thomas
> objected to it for reasons I don't recall clearly.
I think it was along the lines of "it's not the backend's task to teach
SQL". Incidentally, it could be, with the SQL flagger (sec. 4.34).
--
Peter Eisentraut                  Sernanders väg 10:115
peter_e@gmx.net                   75262 Uppsala
http://yi.org/peter-e/            Sweden