Question

This is my Select

using (SqlConnection con = new SqlConnection(dc.Con))
{
    SqlDataAdapter da = new SqlDataAdapter(
            "Select DateOfBirth FROM Patients WHERE HealthNumber='" + cmbHealthNumber.Text+ "'", con);

How do I go about calculating the age of the client changing my above code

I try but I never solve this problem…

Thanks for helping me!

Answer 1

If you only need to retrieve a single DateTime, why not use:

string sqlStmt = "SELECT DateOfBirth FROM dbo.Patients WHERE HealthNumber = @No";

using (SqlConnection con = new SqlConnection(dc.Con))
using (SqlCommand cmd = new SqlCommand(sqlStmt, con))
{
   cmd.Parameters.Add("@No", SqlDbType.VarChar, 20).Value = cmbHealthNumber.Text.Trim();

   con.Open();
   var result = cmd.ExecuteScalar();       
   DateTime dateOfBirth = Convert.ToDateTime(result);
   con.Close();
}

There’s really no need to go through all the trouble of having a SqlDataAdapter and a DataTable or DataSet just for a single value …..

Also: always use parametrized queries! – NO exceptions. Prevent SQL injection – and you definitely don’t want that!