Question about Select Query VERY URGENT

["Sudhakar" <finals27@xxxxxxxxx>]

I have a table in mysql which i have defined as date and the values 
that are inserted have the following format for example : 2007-10-30 
08:02:40

My requirement is to run a select query to retrieve a particular 
column on a specific date ex= "SELECT columnname from tablename 
where columnname='$dt'";

$sd=mysql_query($selectdate);
$sdr=mysql_num_rows($sd);

      if($sdr > 0) 
      { echo "Records found"
      } 
      else { 
      echo "No Records found";
      } 

This works fine only if i manually change the format of the date 
field to the following format = 2007-10-30

I have more than 2000 records in the table so its not a good idea to 
edit the dates.

MY QUESTION IS = without editing the value of the date and the value 
of the date field being 2007-10-30 08:02:40, how can i use a select 
query which would ignore 08:02:40 and consider 2007-10-30 ONLY.

I need to implement this at the earliest. Any help in this regard 
will be greatly appreciated.

Thanks.