[GENERAL] Error from Sub-Select, Simple Example.

[Ian Harding]

OK, here's the deal.  It seems that in this particular situation, if you 
reference an UNQUALIFIED field name in a subselect, the parser thinks it 
is just fine as long as that field name exists SOMEWHERE in the 
referenced tables  Then, the error that gets generated gets lost in the 
mail.

create table one (
   oneid    int,
   onevalue text not null);
create table two (
   twoid    int,
   twovalue text);
insert into one (oneid, onevalue)
select 1,
   case when two.twovalue is null then (select twovalue from one where 
oneid = 1)
       else two.twovalue end
from one left outer join two on one.oneid = two.twoid;

This causes the not null constraint to fire, but if you run the 
subselect by itself, you get

select twovalue from one where oneid = 1;
ERROR:  Attribute "twovalue" not found
Is this a known issue?  I know I should qualify field names where 
confusion might occur, but where did my error go?



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