On 8/8/2012 3:03 PM, email builder wrote:
>
> I don't think mine is so confusing as you suggest if you take a second to
> understand it. Maybe if you read it with some whitespace:
>
> select
> if ('%d' = 'example-2.com',
> IFNULL(
> (select dest from aliases where addr = '%u...@example.com'),
> (select addr from users where addr = '%u...@example.com')
> ),
> NULL)
>
You almost never want to return a NULL result to Postfix using a SQL lookup.
This actually can mean an affirmative instead of a negative result.
A better query might be:
(SELECT dest from aliases where addr = '%u...@example.com' AND '%d' =
'example.net') UNION
(SELECT addr from users where addr = '%u...@example.com' AND '%d' =
'example.net') LIMIT 1
Postfix expects an empty set (i.e. no rows returned) if it is to respond
negatively that a virtual alias does not exist.
Returning NULL does not equal no rows returned.
Brian
N.B. Test all suggested queries before putting into production,
including mine.
