Round #807

Use HAVING to filter aggregate results: orders with more than 5 line items.

```csharp using System; using System.Data; using System.Linq; class Program { static void Main() { // Create a sample DataTable DataTable dt = new DataTable(); dt.Columns.Add("order_id", typeof(int)); dt.Columns.Add("product_id", typeof(int)); dt.Rows.Add(1, 101); dt.Rows.Add(1, 102); dt.Rows.Add(1, 103); dt.Rows.Add(2, 201); dt.Rows.Add(3, 301); dt.Rows.Add(3, 302); dt.Rows.Add(3, 303); dt.Rows.Add(3, 304); dt.Rows.Add(3, 305); dt.Rows.Add(3, 306); dt.Rows.Add(4, 401); dt.Rows.Add(4, 402); dt.Rows.Add(4, 403); dt.Rows.Add(4, 404); dt.Rows.Add(4, 405); dt.Rows.Add(4, 406); dt.Rows.Add(4, 407); // Group by order_id and count the number of rows for each group var grouped = dt.AsEnumerable() .GroupBy(r => r.Field<int>("order_id")) .Select(g => new { order_id = g.Key, num_line_items = g.Count() }); // Filter the results to include only groups with more than 5 rows var filtered = grouped.Where(g => g.num_line_items > 5); // Print the results foreach (var row in filtered) { Console.WriteLine($"order_id: {row.order_id}, num_line_items: {row.num_line_items}"); } } } ```

```csharp using System; using System.Data; using System.Data.SqlClient; class Program { static void Main() { // Connection string string connectionString = "Server=myServerAddress;Database=myDataBase;User Id=myUsername;Password=myPassword;"; // SQL query string query = @" SELECT OrderID, COUNT(*) as LineItemCount FROM Orders GROUP BY OrderID HAVING COUNT(*) > 5 "; // Create a new SqlConnection object using (SqlConnection connection = new SqlConnection(connectionString)) { // Open the connection connection.Open(); // Create a new SqlCommand object using (SqlCommand command = new SqlCommand(query, connection)) { // Execute the query and read the results using (SqlDataReader reader = command.ExecuteReader()) { while (reader.Read()) { Console.WriteLine($"Order ID: {reader["OrderID"]}, Line Item Count: {reader["LineItemCount"]}"); } } } } } } ```