Need to avoid repeated data in a DataGrid

Hi there :)

I am developing a system for my uni course and I am stuck a little problem...

Basically its all about lecturers, students modules etc - A student has many modules, a module has manu students, a lecturer has many modules and a module has many lecturers.

I am trying to get a list of lecturers that run modules associated with a particular student. I am able to get a list of the appropriate lecturers, but some lecturers are repeated because they teach more than one module that the student is associated with.

How can I stop the repeats?

Heres my sql select code in my cs file:

string sqlDisplayLec = "SELECT * FROM student_module sm, lecturer_module lm, users u WHERE sm.user_id=" + myUserid + "" + " AND lm.module_id = sm.module_id " + " AND u.user_id = lm.user_id ";
SqlCommand sqlc2 = new SqlCommand(sqlDisplayLec,sqlConnection);
sqlConnection.Open();
lecturersDG.DataSource = sqlc2.ExecuteReader(CommandBehavior.CloseConnection);
lecturersDG.DataBind();

And here is a pic of my Data Model:
Data Model Screenshot

Any ideas? Many thanks :) !Its ok, sorted it now :)