如何在cakeHP中进行查询联接

我只想问一下如何按照以下SQL语法在CakePHP中进行查询联接

SELECT a.id, SUM( r.jumlah_realisasi) AS jumlah_realisasi, SUM(b.jumlah_budget) AS jumlah_budget, SUM(c.jumlah_contrapos)
FROM accountposts a
LEFT JOIN
(
SELECT accountpost_id, agency_id, SUM(budget_after_changes) AS jumlah_budget
FROM budgets
GROUP BY accountpost_id
) b
ON a.id = b.accountpost_id
LEFT JOIN
(
SELECT accountpost_id, agency_id, SUM(realisation_value) AS jumlah_realisasi
FROM realisations
GROUP BY accountpost_id
) r
ON a.id = r.accountpost_id
LEFT JOIN
(
SELECT accountpost_id, agency_id, SUM(contrapos_value) AS jumlah_contrapos
FROM contraposts
GROUP BY accountpost_id
) c
ON a.id = c.accountpost_id
GROUP BY
a.id

我尝试了这种语法（我使用CakePHP2.x）：

$joins = array(
               array(
                  'table' => 'budgets',
                  'alias' => 'Budget',
                  'type' => 'LEFT',
                  'conditions' => array('Accountpost.id = Budget.accountpost_id')
                ),
                array(
                  'table' => 'realisations',
                  'alias' => 'Realisation',
                  'type' => 'LEFT',
                  'conditions' => array('Accountpost.id = Realisation.accountpost_id')
                ),
                array(
                   'table' => 'contraposts',
                   'alias' => 'Contrapost',
                   'type' => 'LEFT',
                   'conditions' => array('Accountpost.id = Contrapost.accountpost_id')
                ),
         );
        $this->paginate = array(
            'limit' => 60,
            'joins' => $joins,
            'fields' => array('Accountpost.id','Accountpost.explanation','Accountpost.account_code',
                              'SUM(Budget.budget_after_changes) AS jumlah_budget','SUM(Realisation.realisation_value) AS jumlah_realisasi','SUM(Contrapost.contrapos_value) AS jumlah_contrapos'),
            'group' => array('Accountpost.id'),
            'order' => array('Accountpost.id' => 'ASC'),
        );

这是CakePHP的SQL转储：

SELECT `Accountpost`.`id`, `Accountpost`.`explanation`, `Accountpost`.`account_code`, SUM(`Budget`.`budget_after_changes`), `Budget`.`budget_after_changes`, `Realisation`.`realisation_value`, `Contrapost`.`contrapos_value` FROM `realisasi_anggaran`.`accountposts` AS `Accountpost` LEFT JOIN `realisasi_anggaran`.`budgets` AS `Budget` ON (`Accountpost`.`id` = `Budget`.`accountpost_id`) LEFT JOIN `realisasi_anggaran`.`realisations` AS `Realisation` ON (`Accountpost`.`id` = `Realisation`.`accountpost_id`) LEFT JOIN `realisasi_anggaran`.`contraposts` AS `Contrapost` ON (`Accountpost`.`id` = `Contrapost`.`accountpost_id`) WHERE 1 = 1 GROUP BY `Accountpost`.`id` ORDER BY `Accountpost`.`id` ASC LIMIT 60

但SQL语法版本和CakePHP版本的结果不同，在SQL语法中，检查SUM时没有重复的值，但在CakePHP版中，检查SUM时有重复的值。如何以正确的方式将SQL语法实现为cakeHP？