Re: A very simple SQL question.

In article <34849564.3B13DF09@garpac.com>, Jacob Salomon <jake@garpac.com> writes >Constantino Cremidis wrote: > >> Although I have been using SQL for some years I do not remember >> getting this this SQL error. Can someone explain me why this is an >> error. >> >> SELECT a.col1, a.col1, a.col3 FROM table1 a, table2 b >> WHERE ^^^^^^ >> a.col1 = b.col1 AND >> table1.col4 = "SOME_VALUE" >> ^^^^^^>> >> Fails with error 522 Table (table1) not selected in query. >> >> PS. Sorry if this is too obvious but I am just curious. > >Obviously, that last line needed to be: > a1.col4 = "SOME_VALUE" > >Why this is an error? Looks more like a tiny glitch in the parser to >me. If I were Informix, I would probably not put a high priority on If the parser can use table1 and a interchangably above then parsing select col1 from table1 a where table1.col1 = a.col2 (a self join) becomes ambiguous. OK a more complex example is needed but you get the idea. The language becomes undefined. >fixing it because it looks inconsistent and would encourage unclear SQL >(which is normally clear at first glance |:^). > >Just my $0.02 (US) > -- David Williams