Question

The DayDate column in the database is of type DateTime & I’m passing a string formulated using a DateTimePicker in a form. The reader.HasRows always returns false!! I don’t know what I’m doing wrong. Any help would be appreciated. The code that I used is below.

if (!this.con.IsConnected())
{
   this.con.Connect();
}

this.cmd = new OleDbCommand("SELECT DayNo FROM [Calendar] WHERE DayDate = " + date + "", this.con.conObj());

this.reader = cmd.ExecuteReader();
this.reader.Read();

int dayNo;
if (this.reader.HasRows)
{
   dayNo = int.Parse(reader[0].ToString());
}
else
{
   throw new InfoException("The system could not locate the date in the system");
}

Answer 1

The problem is your comparing a Date value to a DateTime so in essence you could possibly be comparing values like this:

DayDate = "2011-12-18 14:22:54"
Date = "2011-12-18 00:00:00"

You need to truncate the time part from your DB dates, try something like this:

"SELECT DayNo FROM [Calendar] WHERE dateadd(dd, 0, datediff(dd, 0, DayDate)) = " + date

Or if using SQL Server 2008 you can do:

"SELECT DayNo FROM [Calendar] WHERE cast(DayDate As Date) = " + date