cakephp set condition on MAX() - mysql

Question

I need max submitted orders in the last 30 days. max field is a virtualField.
public $virtualFields = array(
'max_submitted' => "MAX(`WorkRecord`.`submitted`)"
);
I get error #1054 - Unknown column 'WorkRecord.max_submitted' in 'field list'
SELECT `WorkRecord`.`id`, `Order`.`fee`, `Order`.`order_id`,
`Order`.`min_sources`, `Order`.`min_references`, `Order`.`am_level`,
`Order`.`am_standard`, `Order`.`am_type`, `Order`.`am_subject`, `Order`.`am_word_count`,
`Order`.`ref_style`, `Order`.`service`, `BriefInstalment`.`deadline`,
`BriefInstalment`.`id`, (MAX(`WorkRecord`.`submitted`)) AS `WorkRecord__max_submitted`
FROM `writers`.`work_records` AS `WorkRecord`
RIGHT JOIN `torg`.`temp_orders` AS `Order` ON (`Order`.`order_id` = `WorkRecord`.`order_id` AND `Order`.`status2` > 2 AND `Order`.`am_type` NOT LIKE '%phd%') LEFT JOIN `writers`.`brief_instalments` AS `BriefInstalment` ON (`WorkRecord`.`brief_instalment_id` = `BriefInstalment`.`id`)
WHERE `WorkRecord`.`writer_id` = 7827
AND `WorkRecord`.`withdrawn` IS NULL
AND `WorkRecord`.`max_submitted` BETWEEN NOW() - INTERVAL 30 DAY AND NOW() GROUP BY `Order`.`order_id`

Answer 1

You can't use aggregate function results in where clauses, because the results of the aggregate (e.g. max()) will NOT be available when the where clause is being applied.
Move the max() to a `having:
SELECT ..., max(foo) AS foo
FROM ...
WHERE ...
HAVING foo BETWEEN ...
having is basically applied as the last step just before the results are sent over the client. By that time, all of the calculations/aggregations are done.

Answer 2

For others. Here is what I should have done.
$workRecords = $this->find('all', array(
'fields' => array(
'WorkRecord.id', 'MAX(`WorkRecord`.`submitted`) AS submitted',
'Order.fee', 'Order.order_id', 'Order.min_sources', 'Order.min_references', 'Order.am_level', 'Order.am_standard',
'Order.am_type', 'Order.am_subject', 'Order.am_word_count', 'Order.ref_style', 'Order.service'
),
'conditions' => array(
'WorkRecord.writer_id' => $userId,
'WorkRecord.withdrawn IS NULL'
),
'joins' => array(
array(
'table' => 'torg.temp_orders',
'alias' => 'Order',
'type' => 'RIGHT',
'conditions' => array(
'Order.order_id = WorkRecord.order_id',
'Order.status2 >' => 2,
"Order.am_type NOT LIKE '%phd%'"
)
)
),
'contain' => array(
'BriefInstalment.deadline'
),
'group' => array(
'Order.order_id HAVING `submitted` BETWEEN NOW() - INTERVAL 30 DAY AND NOW()'
)
));