Syntax error (from clause) in query expression in statement

string sqlStatement = "SELECT Orders.[ID], Orders.[Checkintime], Orders.[RoomPrice], Orders.[OrderNo], Particulars.FirstName, Particulars.LastName FROM Orders, where Checkintime between '" + dateOnly + "' and '" + endDateOnly + "', Particulars;";

I tried using this statement to select information from my database but this statement has syntax errors from the FROM clause