Himanshu Upadhyaya <upadhyaya(dot)himanshu(at)gmail(dot)com> writes:
> IMHO below query should replace "NULL" value for ID column with the
> GENERATED IDENTITY value (should insert 1,10 for ID and ID1 respectively in
> below's example), similar to what we expect when we have DEFAULT constraint
> on the column.
Why? Ordinary DEFAULT clauses do not act that way; if you specify NULL
(or any other value) that is what you get. If you want the default
value, you can omit the column, or write DEFAULT.
> Any reason for disallowing NULL insertion?
Consistency and standards compliance.
regards, tom lane