Question

I would like to fill a ComboBox but I want to sort data by one parameter called “id_group”.
I wrote a code but it does not work.
In this line happens an exception which says “incorrect syntax” :

SqlDataReader sd = sc.ExecuteReader();

This is all my code:

int id_group=5;
SqlConnection conn = new SqlConnection();
SqlCommand sc = conn.CreateCommand();
sc.CommandText = "SELECT STUDENT FROM FACULTY WHERE ID_GROUP '" + id_group + "'";
conn.Open();
SqlDataReader sd = sc.ExecuteReader(); //this happens exception - "incorrect syntax"
while (sd.Read())
{
    string graduate = (string)sd["STUDENT"];
    Student_comboBox.Items.Add(graduate);
}
conn.Close();

How to make it work?
Is there other ways to filter data by a parameter?

Answer 1

actually you are missing = on your query, so this should looked like this,

sc.CommandText = "SELECT STUDENT FROM FACULTY WHERE ID_GROUP = '" + 
                                                    id_group + "'";

but please do parameterize it to avoid SQL Injection

sc.CommandText = "SELECT STUDENT FROM FACULTY WHERE ID_GROUP = @groupID";
sc.Parameters.AddWithValue("@groupID", id_group);

SOURCE

• AddWithValue
• Add (recommended to use)