Posted by Ed Murphy on 11/02/07 02:03

Roy Harvey (SQL Server MVP) wrote:

> What is causing the problem is
>
>> (BLOCKED_USERS.blocked_email <> 'bob@a.com')
>
> This turns the LEFT OUTER join into an INNER join by eliminating all
> the NULL BLOCKED_USERS as the NULLs fail this test.

But they'll pass the other part of the test:

OR
(BLOCKED_USERS.blocked_email IS NULL)

That said, I agree that NOT EXISTS is the right way to go.

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