BP_Activity_Activity::get_filter_sql( array $filter_array )

	public static function get_filter_sql( $filter_array ) {

		$filter_sql = array();

		if ( !empty( $filter_array['user_id'] ) ) {
			$user_sql = BP_Activity_Activity::get_in_operator_sql( 'a.user_id', $filter_array['user_id'] );
			if ( !empty( $user_sql ) )
				$filter_sql[] = $user_sql;
		}

		if ( !empty( $filter_array['object'] ) ) {
			$object_sql = BP_Activity_Activity::get_in_operator_sql( 'a.component', $filter_array['object'] );
			if ( !empty( $object_sql ) )
				$filter_sql[] = $object_sql;
		}

		if ( !empty( $filter_array['action'] ) ) {
			$action_sql = BP_Activity_Activity::get_in_operator_sql( 'a.type', $filter_array['action'] );
			if ( ! empty( $action_sql ) )
				$filter_sql[] = $action_sql;
		}

		if ( !empty( $filter_array['primary_id'] ) ) {
			$pid_sql = BP_Activity_Activity::get_in_operator_sql( 'a.item_id', $filter_array['primary_id'] );
			if ( !empty( $pid_sql ) )
				$filter_sql[] = $pid_sql;
		}

		if ( !empty( $filter_array['secondary_id'] ) ) {
			$sid_sql = BP_Activity_Activity::get_in_operator_sql( 'a.secondary_item_id', $filter_array['secondary_id'] );
			if ( !empty( $sid_sql ) )
				$filter_sql[] = $sid_sql;
		}

		if ( ! empty( $filter_array['offset'] ) ) {
			$sid_sql = absint( $filter_array['offset'] );
			$filter_sql[] = "a.id >= {$sid_sql}";
		}

		if ( ! empty( $filter_array['since'] ) ) {
			// Validate that this is a proper Y-m-d H:i:s date.
			// Trick: parse to UNIX date then translate back.
			$translated_date = date( 'Y-m-d H:i:s', strtotime( $filter_array['since'] ) );
			if ( $translated_date === $filter_array['since'] ) {
				$filter_sql[] = "a.date_recorded > '{$translated_date}'";
			}
		}

		if ( empty( $filter_sql ) )
			return false;

		return join( ' AND ', $filter_sql );
	}