Thanks for quick response.
On Tue, Oct 30, 2018 at 6:42 PM Tom Lane <tgl@xxxxxxxxxxxxx> wrote:
Subodh Kumar <subodh.kumar@xxxxxxxxxxxx> writes:
> I have run below query it is created 'test' table without columns
> but table row count is 2.
> please give me clarity about this, i thought it may give syntax error but
> not
> either it must have 2 rows data but both are not happened.
> with ins_test as (select 1 as srno
> union
> select 2)
> select into test from ins_test;
I think you meant to write
with ins_test as (select 1 as srno
union
select 2)
select * into test from ins_test;
or possibly
with ins_test as (select 1 as srno
union
select 2)
select srno into test from ins_test;
What you did write has no columns in the SELECT result clause,
so the INTO creates a table of no columns --- but you get
the expected number of rows.
Postgres allows zero-column tables, and zero-column selects,
because otherwise there are too many weird corner cases;
for instance ALTER TABLE DROP COLUMN would have to reject
dropping the last column. The SQL standard has a different
opinion about which way is less ugly ...
regards, tom lane
