views_handler_argument::summary_query in core/modules/views/handlers/views_handler_argument.inc

Build the info for the summary query.

views_handler_argument_many_to_one::summary_query in core/modules/views/handlers/views_handler_argument_many_to_one.inc

Build the info for the summary query.

views_handler_argument_string::summary_query in core/modules/views/handlers/views_handler_argument_string.inc

Build the summary query based on a string