SELECT COUNT(customers.hash) FROM customers
 LEFT JOIN persons ON persons.agent_code
 WHERE customers.agent_code = persons.agent_code
 GROUP BY customers.agent_code

CREATE TABLE IF NOT EXISTS `customers` (
  `hash` varchar(32) NOT NULL,
  `date_joined` date NOT NULL,
  `agent_code` int(5) NOT NULL DEFAULT '0',
  PRIMARY KEY (`hash`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO `customers` (`hash`, `date_joined`, `agent_code`) VALUES
('0323619e9dd37726ad9aede6b8941022', '2012-09-17', 20004),
('0a5a74acc39773c191b87b759799b0c0', '2012-08-02', 22109),
('1aa4d97ba79dce047d519efe3832b5e5', '2012-07-19', 22109),
('2605578b2e35f01f473591d8f3ed3c51', '2012-08-06', 20003),
('26ce0904a6ea30da9b181a301937664e', '2012-07-30', 20003);




 CREATE TABLE IF NOT EXISTS `persons` (
  `agent_code` int(11) NOT NULL DEFAULT '0',
  PRIMARY KEY (`agent_code`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8;



  INSERT INTO `persons` (`agent_code`) VALUES
  (20003),(20004);

CREATE TABLE IF NOT EXISTS `customers` (
  `hash` varchar(32) NOT NULL,
  `date_joined` date NOT NULL,
  `agent_code` int(5) NOT NULL DEFAULT '0',
  PRIMARY KEY (`hash`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO `customers` (`hash`, `date_joined`, `agent_code`) VALUES
('0323619e9dd37726ad9aede6b8941022', '2012-09-17', 20004),
('0a5a74acc39773c191b87b759799b0c0', '2012-08-02', 22109),
('1aa4d97ba79dce047d519efe3832b5e5', '2012-07-19', 22109),
('2605578b2e35f01f473591d8f3ed3c51', '2012-08-06', 20003),
('26ce0904a6ea30da9b181a301937664e', '2012-07-30', 20003);




 CREATE TABLE IF NOT EXISTS `persons` (
  `agent_code` int(11) NOT NULL DEFAULT '0',
  PRIMARY KEY (`agent_code`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8;



  INSERT INTO `persons` (`agent_code`) VALUES
  (20003),(20004);

SELECT DATE_FORMAT(customers.date_joined, '%W %e') AS 'dt', persons.agent_code AS 'agent', COUNT(*) AS 'customers'
FROM customers
INNER JOIN persons ON persons.agent_code = customers.agent_code
WHERE persons.agent_code = 20003
GROUP BY customers.date_joined, persons.agent_code

SELECT DATE_FORMAT(customers.date_joined, '%W %e') AS 'dt', persons.agent_code AS 'agent', COUNT(*) AS 'customers'
FROM customers
INNER JOIN persons ON persons.agent_code = customers.agent_code
WHERE WEEK(customers.date_joined) = WEEK(NOW())
GROUP BY customers.date_joined, persons.agent_code

select c.agent_code, c.date_joined, count(c.hash)
from
    customers c
    left join
    persons p on p.agent_code = c.agent_code
where weekofyear(date_joined) = weekofyear(current_date)
group by c.agent_code, c.date_joined
;
+------------+-------------+---------------+
| agent_code | date_joined | count(c.hash) |
+------------+-------------+---------------+
|      20004 | 2012-09-17  |             1 |
+------------+-------------+---------------+