むしの手記。

<?php
function find($conditions = null, $fields = array(), $order = null, $recursive = null) {
  if (!is_string($conditions) || (is_string($conditions) && !array_key_exists($conditions, $this->_findMethods))) {
    $type = 'first';
    $query = array_merge(compact('conditions', 'fields', 'order', 'recursive'), array('limit' => 1));
  } else {
    list($type, $query) = array($conditions, $fields);
  }

  $db =& ConnectionManager::getDataSource($this->useDbConfig);
  $this->findQueryType = $type;
  $this->id = $this->getID();

  $query = array_merge(
      array(
         'conditions' => null, 'fields' => null, 'joins' => array(), 'limit' => null,
         'offset' => null, 'order' => null, 'page' => null, 'group' => null, 'callbacks' => true
      ),
      (array)$query
  );

<?php
  function findAll($conditions = null, $fields = null, $order = null, $limit = null, $page = 1, $recursive = null) {
    //trigger_error(__('(Model::findAll) Deprecated, use Model::find("all")', true), E_USER_WARNING);
    return $this->find('all', compact('conditions', 'fields', 'order', 'limit', 'page', 'recursive'));
  }
?>

create table groups (
 id INT(11) unsigned NOT NULL auto_increment,
 sex enum("male","female") NOT NULL default "male",
 age int(11) unsigned NOT NULL default 0,
 modified datetime,
 created datetime,
 PRIMARY KEY (id)
);

insert into groups (sex, age) values
("male",10),
("female",10),
("female",30),
("female",20),
("male",30),
("male",20),
("female",20),
("male",20),
("female",10),
("male",10);

mysql> select * from groups;
+----+--------+-----+----------+---------+
| id | sex    | age | modified | created |
+----+--------+-----+----------+---------+
|  1 | male   |  10 | NULL     | NULL    |
|  2 | female |  10 | NULL     | NULL    |
|  3 | female |  30 | NULL     | NULL    |
|  4 | female |  20 | NULL     | NULL    |
|  5 | male   |  30 | NULL     | NULL    |
|  6 | male   |  20 | NULL     | NULL    |
|  7 | female |  20 | NULL     | NULL    |
|  8 | male   |  20 | NULL     | NULL    |
|  9 | female |  10 | NULL     | NULL    |
| 10 | male   |  10 | NULL     | NULL    |
+----+--------+-----+----------+---------+
10 rows in set (0.00 sec)

mysql> SELECT  age, count(age) as cnt  FROM groups GROUP BY age ORDER BY cnt DESC LIMIT 3 ;
+-----+-----+
| age | cnt |
+-----+-----+
|  10 |   4 |
|  20 |   4 |
|  30 |   2 |
+-----+-----+
3 rows in set (0.00 sec)

<?php
  $fields = array(
                    "conditions" => array(),
                    "fields" => "age, count(Group.age) as cnt",
                    "limit" => 3,
                    "group" => "age",
                    "order" => "ORDER BY cnt DESC",
                  );
  $result = $this->Group->find("all", $fields);
?>

Array
(
    [0] => Array
      (
      [Group] => Array([age] => 10)
      [0] => Array([cnt] => 4)
      )
    [1] => Array
      (
      [Group] => Array([age] => 20)
      [0] => Array([cnt] => 4)
      )
    [2] => Array
      (
      [Group] => Array([age] => 30)
      [0] => Array([cnt] => 2)
      )
)