Add GROUP_CONCAT aggregate function to views
https://www.drupal.org/project/drupal/issues/2902481
Based on patch from DO-2902481-44 and the work from @kapilkumar0324, @kasperg, @jackson.cooper, @b.ravanbakhsh, @Sir-Arturio, @SimeonK, @skyfredox, @stargayte, @achton, @attisan and @naav.
Add GROUP_CONCAT aggregate function to views.
Edited by David Suissa