In "Expert One-on-One Oracle.", p38, Tom Kyte gives the example described
and says "SQL Server supports the ANSI method of Null comparison, just not
by default". This statement is correct, although most SQL installations
(since v7.0) now use the ODBC or OLEDB interface and the ANSI-compliant
option is usually turned ON by default in the connection. That means that
most users and applications actually get the ANSI standard behaviour for
NULL comparisons by default.
However, the ANSI compliant setting does NOT affect the behaviour of unique
constraints / indexes in SQL Server. NULL is always treated as equal to NULL
by unique constraints and indexes.
--
David Portas
SQL Server MVP
--
Received on Sat Oct 30 2004 - 02:56:48 CDT
