Let me tell you that this is a core hacking, so you need to do this every time you do an update.
1. Create simple select field with some values, and set storage format/object as standart -> free -> _content -> name_of_new_column choose alter, varchar (255), and select add column to table
2. edit a root/components/com_content/models/articles.php
find 'urls', 'a.urls', and add 'name_of_new_column', 'a.name_of_new_column',
find 'a.hits, a.xreference, change to 'a.hits, a.name_of_new_column, a.xreference,
find // Filter by featured state, after the switch statement add
// Override New Column
$daerah = $this->getState('filter.name_of_new_column');
switch ($daerah)
{
case 'value1':
$query->where('a.name_of_new_column = \'Value1\'');
break;
case 'value2':
$query->where('a.name_of_new_column = \'Value2\'');
break;
case 'value3':
$query->where('a.name_of_new_column = \'Value3\'');
break;
case 'value4':
$query->where('a.name_of_new_column = \'Value4\'');
break;
default:
break;
}
For now on, every time you trying to filter an article based on the joomla category and the new category simply add
a.name_of_new_column to list.select statement and add
$model->setState('filter.name_of_new_column', $params->get('name_of_module_paramenter', 'default_value_of_parameter'));