using (var conn = new NpgsqlConnection(connString)) { await conn.OpenAsync(); using (var cmd = new NpgsqlCommand("SELECT * FROM customers", conn)) using (var reader = await cmd.ExecuteReaderAsync()) { while (await reader.ReadAsync()) { Console.WriteLine($"Customer Name: {reader.GetString(1)}"); } } }
using (var conn = new NpgsqlConnection(connString)) { await conn.OpenAsync(); var commandText = "SELECT * FROM sales WHERE customer_id = @customerId"; using (var cmd = new NpgsqlCommand(commandText, conn)) { cmd.Parameters.AddWithValue("customerId", customerId); using (var reader = await cmd.ExecuteReaderAsync()) { while (await reader.ReadAsync()) { Console.WriteLine($"Order Date: {reader.GetDateTime(1):yyyy-MM-dd}"); } } } }The package library for Npgsql is "Npgsql".