Синтаксис Sql запроса

private void button4_Click(object sender, EventArgs e)
        {
            SqlCommand comm = new SqlCommand($"SELECT [физика] FROM [успешность] WHERE фамилия = N'%{textBox7.Text}%'");
        }

private void button4_Click(object sender, EventArgs e)
        {
            string connectionString = "server=(local);Initial Catalog=Database211;Integrated Security=True";
            using (SqlConnection connection = new SqlConnection(connectionString))
 
              comm = new SqlCommand($"SELECT [физика] FROM [успешность] WHERE [фамилия] Like '%{textBox7.Text}%'");
 
 
 
        }

private void button4_Click(object sender, EventArgs e)
{
    const string connectionString = "server=(local);Initial Catalog=Database211;Integrated Security=True";
    using (SqlConnection connection = new SqlConnection(connectionString))
    {
        comm = new SqlCommand("SELECT [физика] FROM [успешность] WHERE [фамилия] Like @фамилия");
        comm.Parameters.AddWithValue("@фамилия", $"%{textBox7.Text}%");
        
        connection.Open();
        decimal physics = (decimal)comm.ExecuteScalar();
    }
}