BP_Activity_Activity::get_meta_query_sql( array $meta_query = array() )

	public static function get_meta_query_sql( $meta_query = array() ) {
		global $wpdb;

		$sql_array = array(
			'join'  => '',
			'where' => '',
		);

		if ( ! empty( $meta_query ) ) {
			$activity_meta_query = new WP_Meta_Query( $meta_query );

			// WP_Meta_Query expects the table name at
			// $wpdb->activitymeta.
			$wpdb->activitymeta = buddypress()->activity->table_name_meta;

			$meta_sql = $activity_meta_query->get_sql( 'activity', 'a', 'id' );

			// Strip the leading AND - BP handles it in get().
			$sql_array['where'] = preg_replace( '/^\sAND/', '', $meta_sql['where'] );
			$sql_array['join']  = $meta_sql['join'];
		}

		return $sql_array;
	}