Dim komut As New OleDb.OleDbCommand("SELECT DERSADI FROM DERSLER", baglanti) 
        Dim oku As OleDb.OleDbDataReader 
        oku = komut.ExecuteReader() 
        While oku.Read() 
            ComboBox1.Items.Add(oku("DERSADI"))

Dim komut As New OleDb.OleDbCommand("SELECT DERSADI,DERSLER,OGRETMENLER FROM DERSLER", baglanti) 
        Dim oku As OleDb.OleDbDataReader 
        oku = komut.ExecuteReader() 
        While oku.Read() 
            {
             ComboBox1.Items.Add(oku("DERSADI")) 
             ComboBox2.Items.Add(oku("DERSLER")) 
             ComboBox3.Items.Add(oku("OGRETMENLER")) 
             }