麻烦各位高手看看这段代码怎么改，为什么不能同时删除两张表里的行

protected void GridView2_RowDeleting(object sender, GridViewDeleteEventArgs e)
    {
        cn.Open();
        GridViewRow row = GridView2.Rows[e.RowIndex];
        int t_id = int.Parse(GridView2.DataKeys[e.RowIndex].Values[0].ToString());
        SqlDataReader dr;
        string sql = "Delete From teacher,users Where t_id='" + GridView1.DataKeys[e.RowIndex].Value.ToString() + "' user_id='" + GridView1.DataKeys[e.RowIndex].Value.ToString() + "'";
        SqlCommand cm = new SqlCommand(sql, cn);
        dr = cm.ExecuteReader();
        GridView1.EditIndex = -1;
        cn.Close();
    } --------------------编程问答--------------------        string sql = "Delete From teacher,users Where t_id='" + GridView1.DataKeys[e.RowIndex].Value.ToString() + "' user_id='" + GridView1.DataKeys[e.RowIndex].Value.ToString() + "'";

没听说过 sql 有这种写法delete from teacher，users wher
要么你delete from teacher where id = 。。
delete from users where id = 。。分开写

或者就用触发器 --------------------编程问答-------------------- string sql="delete from teacher where t_id='" + GridView1.DataKeys[e.RowIndex].Value.ToString() + "'; delete from users where user_id='" + GridView1.DataKeys[e.RowIndex].Value.ToString() + "'"; --------------------编程问答-------------------- 的确没见过这么些的，分开写吧， --------------------编程问答-------------------- 各位分开写说是“索引超出范围。必须为非负值并小于集合大小。参数名: index”

补充：.NET技术 ,  ASP.NET