On Fri, Jun 25, 2010 at 14:06, Peter Eisentraut <peter_e@gmx.net> wrote:
> Second version:
Hi!
Ive looked this over. Looks great! I have some nits about the
documentation and comments ( non issues like referencing primary keys
when it really means not null unique indexes :-P ), but on the whole
it works and looks good.
The only corner case I have run into is creating a view with what I
would call an implicit 'not null' constraint. Demonstration below:
create table nn (a int4 not null, b int4, unique (a));
select * from nn group by a; -- should this work? I think not?
a | b
---+---
(0 rows)
create view vv as select a, b from nn group by a;
select * from vv;a | b
---+---
(0 rows)
=# alter table nn alter column a drop not null;
=# select * from nn group by a; -- ok, broken makes sense
ERROR: column "nn.b" must appear in the GROUP BY clause or be used in
an aggregate function
LINE 1: SELECT * from nn group by a;
=# select * from vv; -- yipes should be broken?a | b
---+---
(0 rows)
Im thinking we should not allow the "select * from nn group by a;" to
work. Thoughts?
(FYI I do plan on doing some performance testing with large columns
later, any other requests?)
