You can access the same column information about the results of a query that you can for table schemas. See Columns for the columns returned.

Retrieving Result Set Metadata

You can use the GetSchemaTable method of the D365BusinessCentralDataReader to retrieve result set metadata. Call GetSchemaTable after calling ExecuteReader.

Each row of the DataTable describes a column in the query's result.

C#

string connectionString = "InitiateOAuth=GETANDREFRESH;OrganizationUrl=https://api.businesscentral.dynamics.com/v1.0/api/v1.0";

using (D365BusinessCentralConnection conn = new D365BusinessCentralConnection(connectionString)) {
  D365BusinessCentralCommand cmd = new D365BusinessCentralCommand("SELECT * FROM Accounts WHERE Name <> 'MyAccount'", conn);
  D365BusinessCentralDataReader rdr = cmd.ExecuteReader();
  DataTable schemaTable = rdr.GetSchemaTable();
  foreach (DataRow row in schemaTable.Rows) {
    foreach (DataColumn col in schemaTable.Columns) {
      Console.WriteLine("{0}: {1}", col.ColumnName, row[col]);
    }
  }
}

VB.NET

Dim connectionString As String = "InitiateOAuth=GETANDREFRESH;OrganizationUrl=https://api.businesscentral.dynamics.com/v1.0/api/v1.0"

Using conn As New D365BusinessCentralConnection(connectionString)
  Dim cmd As New D365BusinessCentralCommand("SELECT * FROM Accounts WHERE Name <> 'MyAccount'", conn)
  Dim rdr As D365BusinessCentralDataReader = cmd.ExecuteReader()
  Dim schemaTable As DataTable = rdr.GetSchemaTable()
  For Each row As DataRow In schemaTable.Rows
    For Each col As DataColumn In schemaTable.Columns
      Console.WriteLine("{0}: {1}", col.ColumnName, row(col))
    Next
  Next
End Using