Kirron says:
string
query =
" Select Bill_No , Name, Address, MobileNo,Sl_No,ItemName,Size,Quantity,Rate,Amount,Total_Amount,Payment,Balance,Date"
+
"from SALES"
+ $
" where Date between '{dtFromDate.Value}' and '{ dtToDate.Value}'"
;
Try by below code also check the query string object value by debugging also be sure your table name SALES have date as a column in table.
string query = " Select Bill_No , Name, Address, MobileNo,Sl_No,ItemName,Size,Quantity,Rate,Amount,Total_Amount,Payment,Balance,Date" +
"from SALES" + " where Date between '"+dtFromDate.Value+ "' and '"+ dtToDate.Value+"'";