CakePHP 3 limit of association does not works - cakephp

Question

Below are the lines from cakephp documentation which does not work.
Changing Fetching Strategies
As you may know already, belongsTo and hasOne associations are loaded using a JOIN in the main finder query. While this improves query and fetching speed and allows for creating more expressive conditions when retrieving data, this may be a problem when you want to apply certain clauses to the finder query for the association, such as order() or limit().
For example, if you wanted to get the first comment of an article as an association:
$articles->hasOne('FirstComment', [
'className' => 'Comments',
'foreignKey' => 'article_id'
]);
In order to correctly fetch the data from this association, we will need to tell the query to use the select strategy, since we want order by a particular column:
$query = $articles->find()->contain([
'FirstComment' => [
'strategy' => 'select',
'queryBuilder' => function ($q) {
return $q->order(['FirstComment.created' =>'ASC'])->limit(1);
}
]
]);
THanks

Answer 1

When working with hasOne note that CakePHP will strip the ORDER BY clause from the query after the queryBuilder is called. The queryBuilder is used to create the joining conditions for the JOIN clause. There is no SQL syntax that allows a ORDER BY clause inside an ON (expression) for a join.
You also have to use a SELECT strategy for hasOne if you want to use ORDER BY.
You can get around this issue by using a custom finder.
$articles->hasOne('FirstComment', [
'className' => 'Comments',
'foreignKey' => 'article_id',
'strategy' => Association::STRATEGY_SELECT,
'finder' => 'firstComment'
]);
In your CommentsTable class define a custom finder which sets the order.
public function findFirstComment($q) {
return $q->order([$this->aliasField('created') =>'ASC']);
}
CakePHP won't strip the ORDER BY clauses for hasOne when added by custom finders.
Note: The custom finder has to be in the association's target, not the source table.