SELECT
      `tblinvoices`.`userid` AS `accountid`,
      COUNT(*) AS `pastdueinvoices`,
      CONCAT('$',FORMAT(SUM(`tblinvoices`.`total`),2)) AS `pastduebalance`,
      DATEDIFF(NOW(),`tblinvoices`.`duedate`) AS `pastduedays`,
      `tblclients`.`firstname`,
      `tblclients`.`lastname`,
      `tblclients`.`companyname`
   FROM
      `tblinvoices`
   JOIN
      `tblclients`
   ON
      `tblclients`.`id` = `tblinvoices`.`userid`
   LEFT OUTER JOIN
      `accountspastdue_clients`
   ON
      `accountspastdue_clients`.`id` = `userid`
   AND
      (
         `accountspastdue_clients`.`dismissuntildate` <> '0000-00-00'
      AND
         `accountspastdue_clients`.`dismissuntildate` >= NOW()
      )
   OR
      (
         `accountspastdue_clients`.`dismissuntilchange` = 1
      AND
         `accountspastdue_clients`.`pastduebalance` <> `pastduebalance`
      )
   OR
      (
         `accountspastdue_clients`.`dismissuntilchange` = 1
      AND
         `accountspastdue_clients`.`pastdueinvoices` <> `pastdueinvoices`
      )
   WHERE
      `tblinvoices`.`status` = 'Unpaid'
   AND
      `tblinvoices`.`duedate` < NOW()
   AND
      `accountspastdue_clients`.`id` IS NULL
   GROUP BY
      `tblinvoices`.`userid`
   ORDER BY
      `tblinvoices`.`duedate`