Query not returning value

[EchoFool]

I have a query which checks a timestamp to "NOW()" but it returns nothing.. i echo it and i get nothing , yet with error reporting on it doesn't give me undefined error :S

 

This is what i got:

 

LastAction - 0000-00-00 00:00:00 -Timestamp format

 

SELECT *,
TIMESTAMPDIFF(MINUTE,'NOW()','LastAction') AS MinutesAgo 
FROM ".tablename().".user_data 
WHERE UserID='$UserID'

 

Then i echo it later on :

$row = mysql_fetch_assoc($SELECT);
Echo 'Minutes ago: '.$row['MinutesAgo'];Echo '<br>';
Echo 'Username: '.$row['Username']; Echo '<br>';

 

The return gives:

Minutes ago:

Username: Username1

Any idea why this is happening?

[PFMaBiSmAd]

Both NOW() and LastAction are not strings. Why are they enclosed in single-quotes in the query?

[EchoFool]

I was given the query from a user on phpfreaks a while ago - so i assumed that was how they are typed ...