Как вывести результат функции в label?

private void button5_Click(object sender, EventArgs e)
        {
            
            using (SqlConnection con = new SqlConnection(conString))
            {
                con.Open();
                SqlCommand command = new SqlCommand("SELECT * FROM dbo.SumProceeds('" + textBox1.Text + "','" + textBox2.Text + "')", con);
                label5.Text = command.ExecuteScalar().ToString();
                con.Close();
            }
}

SqlCommand command = new SqlCommand("SELECT * FROM dbo.SumProceeds(@date1, @date2)", con);
command.Parameters.AddWithValue("@date1", DateTime.Parse(textBox1.Text, cultureInfo));
command.Parameters.AddWithValue("@date2", DateTime.Parse(textBox2.Text, cultureInfo));

label5.Text = command.ExecuteScalar().ToString()

var cultureInfo = System.Globalization.CultureInfo.CurrentCulture;
SqlCommand command = new SqlCommand("SELECT dbo.SumProceeds(@date1, @date2)", con);
command.Parameters.AddWithValue("@date1", DateTime.Parse(textBox1.Text, cultureInfo));
command.Parameters.AddWithValue("@date2", DateTime.Parse(textBox2.Text, cultureInfo));

SqlCommand command = new SqlCommand("SELECT dbo.SumProceeds(@date1, @date2)", con);
command.Parameters.AddWithValue("@date1", dateTimePicker1.Date);
command.Parameters.AddWithValue("@date2", dateTimePicker2.Date);