unsetSortingColumns
unsetSortingColumns(array $columns)
Unset the sorting on the datagrid from column ordering and sorting. Especially useful when you want to disable sorting for specific columns.
Example
$crud->setTable('customers');
$crud->setSubject('Customer', 'Customers');
$crud->columns(['customerName','phone','creditLimit', 'addressLine1', 'salesRepEmployeeNumber']);
$crud->unsetSortingColumns(['phone', 'addressLine1', 'salesRepEmployeeNumber']);
$output = $crud->render();