How do I get my code to work? Inner join table as well as CRUD system help please

import sqlite3
loop = True

def purchase_info():
    conn = sqlite3.connect('car.db')
    cursor = conn.cursor()
    sql = '''SELECT clients.First_name, clients.Surname, cars.Make, cars.Model, purchase.Date_of_Purchase FROM
((purchase INNER JOIN cars ON purchase.numbID = cars.numbID) INNER JOIN clients ON purchase.ClientID = clients.ClientID)
WHERE purchaseID = ?''';
    cursor.execute(sql)
    result = cursor.fetchall()
    for row in result:
        print ("First_name: " + str(row[0]) +", Surname: " +
              str(row[1]) + ", Make: " + str(row[2]) + ",Model: " +
               str(row[3]) + ",Date_of_Purchase: " +str(row[4]))
    

def displaymenu():
    print("1 to display records")
    print("2 to enter records")
    print("3 to update records")
    print("4 to delete records")
    print("5 to exit the menu\n")
    #print("")
def select():
    conn = sqlite3.connect('car.db')
    cursor = conn.cursor()
    sql = 'SELECT * FROM cars';
    cursor.execute(sql)
    result = cursor.fetchall()
    for row in result:
        print ("numbID: " + str(row[0]) +", Make: " +
              str(row[1]) + ", Model: " + str(row[2]) + ",Colour: " +
               str(row[3]) + ",Year: " +str(row[4]) + ",Transmission:" +
               str(row[5]) + ",Price: "+str(row[6]) + ",Number In Stock:" +str(row[7]))
               
def insert():
    var_choice = int(input("Select the number of cars to input "))
    var_count = 1
    while var_choice >=var_count:
        var_Make = str(input("Input car make. "))
        var_Model = str(input("Input car model. "))
        var_Colour = str(input("Input car's colour. "))
        var_Year = str(input("Input car release date."))
        var_Transmission= str(input("Input car's transmission type."))
        var_Price=str(input("Input car's price."))
        var_Stock= str(input("Input car stock number."))
        var_insert = []
        var_insert.append(var_Make)
        var_insert.append(var_Model)
        var_insert.append(var_Colour)
        var_insert.append(var_Year)
        var_insert.append(var_Transmission)
        var_insert.append(var_Price)
        var_insert.append(var_Stock)
        conn = sqlite3.connect('car.db')
        cursor = conn.cursor()
        print(var_insert)
        cursor.execute('insert INTO cars(Make, Model, Colour, Year,Transmission,Price,Stock)VALUES (?,?,?,?,?,?,?);', var_insert)
        conn.commit()
        var_count += 1
def update():
    var_updt = str(input("Give the ID number of the car to update. "))
    var_updt_Make = str(input("Give the new make of car. "))
    var_updt_Model= str(input("Give the new model of car."))
    var_updt_Colour= str(input("Give the new colour of the car."))
    var_updt_Year= str(input("Give the new year of the car."))
    var_updt_Transmission= str(input("Give the new transmission of the car."))
    var_updt_Price= str(input("Give the new pricing of the car."))
    var_updt_Stock = str(input("How many cars in stock?"))
    var_update = []
    var_update.append(var_updt_Make)
    var_update.append(var_updt_Model)
    var_update.append(var_updt_Colour)
    var_update.append(var_updt_Year)
    var_update.append(var_updt_Transmission)
    var_update.append(var_updt_Price)
    var_update.append(var_updt_Stock)
    var_update.append(var_updt)
    conn = sqlite3.connect('car.db')
    cursor = conn.cursor()
    print(var_update)
    cursor.execute('UPDATE cars SET Make = ?, Model= ?, Colour=?, Year=?, Transmission=?, Price=?, Stock=? WHERE numbID =?', var_update)
    
    conn.commit()
def delete():
    var_del =[]
    var_del_choice = str(input("Give the ID number of the car record to delete."))
    var_del.append(var_del_choice)
    #print (var_del)
    conn = sqlite3.connect ('car.db')
    cursor = conn.cursor()
    cursor.execute ('DELETE FROM car WHERE numbID =?', var_del)
    conn.commit()

while loop:
    displaymenu()
    var_choice = input("Please make your choice using numbers 1-5.")
    print("")
    if var_choice =='1':
        select()
    elif var_choice =='2':
         insert()
    elif var_choice =='3':
          update()
    elif var_choice =='4':
          delete()
    elif var_choice =='5':
            #this next statment turns the loop off
          loop= False
    elif var_choice =="":
            # the double quotes together are a null value
         print("Please enter a number.")
    else:
         print("Invalid input.")