You have a list with a linked table? For example in the AdminController you display Customer, right? What if you want to separate first names and last names ; and then perform a simple search?

It will trigger an error! You have to use the filter_key parameter. Here’s how.

Let’s say you have

LEFT JOIN category_lang as cl [...]
LEFT JOIN customers as c [...]

You can then use

$this->fields_list = [
  'category' => ['title' => 'Category', 'filter_key' => 'cl!name'], // mind the ! as a separator
  'customer' => ['title' => 'Customer', 'filter_key' => 'c!firstname'],