How can I make to make a complex query for my login system?

Question

I want a login system which relates to a register database I made

I am trying to make a complex query which takes the user input:

    Entry(self.root,
          textvariable=self.username)  ##There is more but I want this to be as minimal as possible 
          
    Entry(self.root,
          textvariable=self.password,
          show="*")
             

This user input then gets compared with the one in the database. This is where I am finding it diffucult:

def login(self):
    con = sqlite3.connect("register.db")  ##The database which I want to open and compare user inputs to 
    c = con.cursor()
    c.execute("SELECT * FROM register")
    slist = c.fetchall()
    values = [row[0] for row in slist]
    values2 = [row[1] for row in slist]
    if self.username.get() == values and self.password.get()==values2:
        command=self.invcon  ##A external thing I want to open if the user enters the data in correctly
    else:
        messagebox.showerror("Error","Error"parent=self.root)
    con.commit()
    con.close()

The error which is now happening is instead of opening the new window it moves into the else and pops up with the error box. Database

Answer 1

I don't understand all of the errors but when selecting something from a table (in this case 'register') you can either select things by listing them up like:

c.execute("SELECT username, password ... FROM register")

or you simply select everything:

c.execute("SELECT * FROM register")

In this case you did both ("SELECT username * FROM ...") which is why there could be an error.