sql_3.py

# connect to existing database
conn = sqlite3.connect('.\sql_db\Demo_table.db')
cur = conn.cursor()

# create table in database
cur.execute('''CREATE TABLE CUSTOMER(
                User_ID INTEGER PRIMARY KEY NOT NULL,
                Product_ID INTEGER NOT NULL,
                Name TEXT NOT NULL,
                Gender TEXT NOT NULL,
                AGE INTEGER NOT NULL,
                CITY TEXT);
                ''')

# commit and save changes to database
conn.commit()