Question

I have two tables: users and posts. I’m trying to select any users that have at least one post.

I’m guessing this require either a join or a subselect. Is there something in CakePHP that makes this simple?

Answer 1

Use counter caching, see http://book.cakephp.org/2.0/en/models/associations-linking-models-together.html#belongsto

counterCache: If set to true the associated Model will automatically
increase or decrease the “[singular_model_name]_count” field in the
foreign table whenever you do a save() or delete(). If it’s a string
then it’s the field name to use. The value in the counter field
represents the number of related rows. You can also specify multiple
counter caches by using an array where the key is field name and value
is the conditions. E.g.:

array(
‘recipes_count’ => true,
‘recipes_published’ => array(‘Recipe.published’ => 1) ) counterScope: Optional conditions array to use for updating counter
cache field.

No additional query needed in this case. It will automatically in- and decrease the count in the users table if you add/delete posts.

Example:

public $belongsTo = array(
    'User' => array(
        'foreignKey' => 'user_id',
        'counterCache' => true,
        'counterScope' => array(
            'published' => 1)));