Norman Elton wrote:
I've got a table that tracks expiration dates. Currently, if the record hasn't expired, the column is stored as NULL. In order to find records that haven't expired, I search for "WHERE expire_at > NOW() OR expire_at IS NULL". This seems dirty, and I suspect it makes my indexes very angry. I suppose I could pick some arbitrary future date (Dec 31 2999) to use in place of NULL. Is there a better way? Surely I'm not the first to run into this!
If the field is only updated when the record expires, then a simple "where expire_at is NULL" will do. You only need to compare expiration dates with NOW() if they can be in the future - which, from your description, isn't possible.
If an expiry date can be either future, past or non-existent, then your existing selector is as good as any.
Mark -- http://mark.goodge.co.uk - my pointless blog http://www.good-stuff.co.uk - my less pointless stuff -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
