cakephp 3 - Impossible to generate condition with empty list

Question

In cakephp 3 query gives error when added 'IN' condition in contain query.

$itemsquery = $Students->find('all');
$itemsquery->select(['Students.id']);

$itemsquery->matching('CategoriesStudents');
$itemsquery->contain([
'CategoriesStudents' => function ($q) use ($category_ids) {
return $q->where(['CategoriesStudents.category_id IN' => $category_ids]);
}
]);

// debug($itemsquery);
$items = $itemsquery->toArray(); 

Error

Impossible to generate condition with empty list of values for field (`CategoriesStudents`.`category_id`)

Error: An Internal Error Has Occurred.
An Internal Server Error Occurred

Tables are

1. categories_students

category_id, student_id

2. students

3. category

$category_ids array

Array
(
    [1] => 57
    [2] => 60
    [3] => 58
    [4] => 13
    [5] => 78
    [6] => 56
    [7] => 59
    [8] => 79
    [9] => 95
    [10] => 94
    [11] => 96
    [12] => 93
    [13] => 82
    [14] => 23
    [15] => 82
    [16] => 14
    [17] => 16
    [18] => 101
    [19] => 14
)

Please help

Answer 1

You can't leave IN operator empty, you must put into it something like NULL. Try to cover the case for an empty Array:

return $q->where(
     ['CategoriesStudents.category_id IN' =>
        count($category_ids) > 0 ?  $category_ids : [null])
]);

Reference: Empty IN clause parameter list in MySQL