Question

There are several questions about using .Net DateTime in Sql statements but none of them solved my problem.

I’m using the following code to query an Oracle database :

private DataTable QueryByIdAndDate(string id, DateTime fdate, DateTime tdate) {
    string query = "SELECT * FROM table WHERE ID = :id AND DATE_TIME BETWEEN :from AND :to"
    DbCommand cmd = db.CreateCommand();
    cmd.CommandType = CommandType.Text;
    cmd.CommandText = query;

    DbParameter fromDate = CreateDateParameter(cmd, fdate);
    fromDate.ParameterName = "from";
    DbParameter toDate = CreateDateParameter(cmd, tdate);
    toDate.ParameterName = "to"; 
    DbParameter idParam = CreateStringParameter(cmd, id);
    idParam.ParameterName = "id";

    cmd.Parameters.AddRange(new DbParameter[] { fromDate, toDate, idParam });
    return db.ExecuteQuery(cmd);
}

private DbParameter CreateDateParameter(DbCommand cmd, DateTime date) {
    DbParameter param = cmd.CreateParameter();
    param.DbType = DbType.DateTime;
    param.Direction = ParameterDirection.Input;
    param.Value = date;
    return param;
}

But it does not work properly. When trying the code out like so:

DataTable result = QueryByIdAndDate("12345", DateTime.Now, DateTime.Now.AddDays(1));

It gives the following error:
ORA-01847: day of month must be between 1 and last day of month

I’m assuming it has to do with the way the DateTime is formatted but I don’t know the proper way to fix this in a reliable way.

Answer 1

(As per comments…)

It looks like in this case, the order of the parameters matters… despite the fact that you’ve given them names. I wouldn’t have expected this, and it’s the sign of a somewhat broken driver, but changing your code to:

cmd.Parameters.AddRange(new DbParameter[] { idParam, fromDate, toDate });

should fix it. (This isn’t necessarily the way you should be constructing your parameters, by the way, but that’s somewhat immaterial here.)

Do not start specifying the date/time values as strings. It’s a really bad idea to introduce any more string conversions than you need.