"AND", [ "key" => "sp_results", "value" => '"outcome"', "compare" => "LIKE", ], [ "key" => "sp_results", "value" => 's:7:"outcome";a:0:{}', // i.e. a blank outcome "compare" => "NOT LIKE", ], ]; } elseif (!$has_outcome) { return [ "relation" => "OR", [ "key" => "sp_results", "value" => '"outcome"', "compare" => "NOT LIKE", ], [ "key" => "sp_results", "value" => 's:7:"outcome";a:0:{}', // i.e. a blank outcome "compare" => "LIKE", ], ]; } } // Add the custom filter dropdown function outcome_filter_dropdown() { $current_screen = get_current_screen(); if ($current_screen->id == "edit-sp_event") { if (isset($_GET["has-outcome"])) { switch ($_GET["has-outcome"]) { case 'true': $selected="has-outcome";break; case 'false': $selected="has-no-outcome";break; case '': $selected='';break; } }; ?> >All Outcomes >Missing Outcome >Has Outcome set("meta_query", $meta_query); } elseif ($_GET["has-outcome"] == "true") { $meta_query = get_sp_event_has_outcome_meta_query_args(true); $query->set("meta_query", $meta_query); } } } add_action("pre_get_posts", "outcome_filter_query");