Re: UNIQUE not honoured for NULL - Mailing list pgsql-bugs

David Newall wrote:
> PostgreSQL version:  7.4.3 (RPMs from ftp.au.postgresql.org)
>
> Operating Sysem: Fedora Core 1
>
> CREATE TABLE t(i integer UNIQUE);
> INSERT INTO t VALUES (null);
> INSERT INTO t VALUES (null);
> SELECT coalesce(i,-999) FROM t;
>  coalesce
> ----------
>      -999
>      -999
> (2 rows)

NULL = NULL is not true, so the rows are not equal.