# www.plus2net.com
# download updated script at https://www.plus2net.com/python/tkinter-OptionMenu-proj3-sqlite.php
import sqlite3
my_conn = sqlite3.connect('my_db.db')
###### end of connection ####

query="SELECT distinct(class) as class FROM student"
r_set=my_conn.execute(query);
my_list = [r for r, in r_set] # create a  list 

import tkinter as tk
my_w = tk.Tk()
my_w.geometry("250x200")  # Size of the window 
my_w.title("www.plus2net.com")  # Adding a title

options = tk.StringVar(my_w)
options.set(my_list[0]) # default value

om1 =tk.OptionMenu(my_w, options, *my_list)
om1.grid(row=2,column=5)

my_w.mainloop()