逗号附近的语法不正确

Question

Here's an ASPX code snippet from when I was trying to get multiple values from a session. I am getting an error: "Incorrect syntax near comma" (marked the line in the snippet):

SqlCommand cmd1 = new SqlCommand("select plugin_id from profiles_plugins where profile_id=" + Convert.ToInt32(Session["cod"]), con);
        SqlDataReader dr1 = cmd1.ExecuteReader();
        var yourlist =new List<Int32>();
        if (dr1.HasRows)
        {
            while (dr1.Read())
            {
                yourlist.Add(Convert.ToInt32(dr1[0]));
            }
        }

        //String str1 = String.Join(", ", yourlist.Select(o => o.ToString()).ToArray());
            dr1.Close();
        cmd1.Dispose();
        Array k= yourlist.ToArray();
        Int32 a =Convert.ToInt32( k.GetValue(0));
        Int32 b =Convert.ToInt32( k.GetValue(1));
        Int32 c =Convert.ToInt32( k.GetValue(2));
        Int32 d =Convert.ToInt32( k.GetValue(3));
        SqlCommand cmd2 = new SqlCommand("select id,name from plugins where id =(" + a + " or " + b + " or " + c + " or " + d +  ")" , con); /// Error here?
        SqlDataReader dr2 = cmd2.ExecuteReader(); ///Error here?
        if (dr2.HasRows)
        {
            while (dr2.Read())
            {
                ListBox2.DataSource = dr2;
                ListBox2.DataBind();
            }
        }
        dr2.Close();
        cmd2.Dispose();
con.Close();

What am I missing?

Answer 1

SQL Query is wrong. Change it to:

    SqlCommand cmd2 = new SqlCommand("select id,name from plugins   
where id in(" + a + " , " + b + " , " + c + " , " + d +  ")" , con);

Answer 2

Error in this line. Try this

SqlCommand cmd2 = new SqlCommand("select id,name from plugins where id =" + a + "or id =" + b + " or id =" + c + " or id =" + d +  "" , con)

Answer 3

In your case in stead of multiple conditions OR I would suggest to use IN clause in your SQL query, and instead of . .. + "" + ... I would use String.Format

SqlCommand cmd2 = new SqlCommand(String.Format("select id,name from plugins where id IN ({0}, {1}, {2}, {3}", a, b, c, d,) con);

Also if you would have the same or similar error in the future you may check your query directly on SQL Server. Just open New Query window and copy your SQL query there and then run it. In that case it would be something like:

select id,name from plugins where id IN (1, 2, 3, 4)