public static ZonedDateTime convertToDateTime(BigDecimal value, TimeZone tz) {
        if (value == null) {
            return null;
        }

        return convertToDateTime(value, tz != null ? tz.toZoneId() : UTC_ZONE);
    }
Converts big decimal to date time.

@param value big decimal
@param tz    time zone, null is treated as UTC
@return date time
clickhouse-data/src/main/java/com/clickhouse/data/ClickHouseValues.java