$sth = $dbh->prepare( "
 SELECT COUNT(*) As Total
   ## long complicated WHERE stuff
  " ) || die "Error: " . $dbh->errstr;

  $sth->execute() || die "Error: " . $dbh->errstr;    
  if( $Total > 0 ){
     ## only if it passes this condition, do the REAL
     ## select and print out the results
  }