Click sorting does not work on Completed Process Time in Views

Problem/Motivation

Enabling click sorting Completed Process Time field in Views produces an "Column not found: 1054 Unknown column 'unknown' in 'order clause'" error.

Steps to reproduce

1. Edit Maestro All Flows View
2. Edit Format Table Settings
3. Make "Completed" field sortable
4. Click table header for completed

Proposed resolution

Add clickSort method to maestro_process_completed_time views_field_hander

function clickSort($order) {
  $this->query->addOrderBy('maestro_process', 'completed', $order, NULL);
}

Remaining tasks

User interface changes

API changes

Data model changes