c# 读取数据库问题
string strconn = "Server=localhost\\sqlexpress; database = model; integrated security=SSPI ";
SqlConnection conn = new SqlConnection(strconn);
string sql = "select mm from dl where name='zw'";
SqlCommand sda = new SqlCommand(sql, conn);
conn.Open();
MessageBox.Show(sda.ExecuteNonQuery().ToString());
conn.Close();
为啥显示的是-1,我数据库里明明有对应的数据?帮我改下。