Error in my WHERE clause - please help

  • Thread starter Thread starter Alex
  • Start date Start date
A

Alex

Why am I getting the following error?

/*
TYPE: System.Data.OleDb.OleDbException
MESSAGE: Operator/operand type mismatch.
*/

It happens at the ExecuteReader() statement.

I am trying to access a dbf file and it works when I don’t include any
dates in my WHERE clause (i.e. my clause looks like: WHERE termcd =
‘SA’). Here is the relevant code:

/*
string sql = "SELECT tel FROM results WHERE termcd = 'SA' AND lcdate
= " + dateFrom.Value.ToString(@"MM/dd/yyyy") + " AND lcdate <= " +
Click to expand...
dateTo.Value.ToString(@"MM/dd/yyyy");
OleDbConnection con = new OleDbConnection(resultsFolder);
OleDbCommand cmd = new OleDbCommand(sql, con);
OleDbDataReader r = null;

con.Open();
r = cmd.ExecuteReader();
*/

Do I need to surround the dates with hashes or something for them to
register as dates?
 
Alex,

The two date literal values need to be enclosed in the appropriate literal
string delimiter.

Your SQL string gets expanded into something like this:

SELECT tel FROM results
WHERE termcd = 'SA'
AND lcdate >= 05/05/2004 AND lcdate <= 05/06/2004

Also - you should consider using the BETWEEN clause - try something like
this

SELECT tel FROM results
WHERE termcd = 'SA'
AND lcdate BETWEEN '05/05/2004' AND '05/06/2004'

regards

roy fine
 
Roy Fine said:
The two date literal values need to be enclosed in the appropriate literal
string delimiter.

Your SQL string gets expanded into something like this:

SELECT tel FROM results
WHERE termcd = 'SA'
AND lcdate >= 05/05/2004 AND lcdate <= 05/06/2004

Also - you should consider using the BETWEEN clause - try something like
this

SELECT tel FROM results
WHERE termcd = 'SA'
AND lcdate BETWEEN '05/05/2004' AND '05/06/2004'
Click to expand...

Rather than specify the dates in the SQL itself, you should also
consider (very strongly!) using command parameters. See
OleDbCommand.Parameters for an example.
 
Alex,

The two date literal values need to be enclosed in the appropriate literal
string delimiter.

Your SQL string gets expanded into something like this:

SELECT tel FROM results
WHERE termcd = 'SA'
AND lcdate >= 05/05/2004 AND lcdate <= 05/06/2004

Also - you should consider using the BETWEEN clause - try something like
this

SELECT tel FROM results
WHERE termcd = 'SA'
AND lcdate BETWEEN '05/05/2004' AND '05/06/2004'
Click to expand...

Thanks that's what I needed to do but with {} braces.
 
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