Ask HN: I need help with MYSQL and timestamps

I'm using an RSS parser called SimplePie for an RSS reader I built. Unfortunately, SimplePie does not insert a value into the db for items without a timestamp which is making things very wonky for users with certain feeds.

I need to add a default value (the time of insertion) to items without a timestamp. I'm new to PHP, but an RSS app I built on SimplePie has been getting a lot of users since the Google Reader shutdown and I need to fix this, ASAP.

A recent timestamp looks like this... "1326009170"

Using MYSQL/PHPadmin, can I set a default timestamp for this field that matches the format above?