Hey @fairymemay
Kindly use this in your query condition,
DateTime.ParseExact(x("Issue Date").ToString, "yyyyMMdd", System.Globalization.CultureInfo.InvariantCulture) <= Date.ParseExact(x("วันที่รับเล่ม (<=)").ToString.Trim,"dd/M/yyyy",System.Globalization.CultureInfo.InvariantCulture)
The above condition will only do the date column comparison as requested for other columns you can add along with this.
Thanks
#nK