A
If what you want is to twist the elements that are in one of the lists but not the other you can use the method https://docs.python.org/3/library/stdtypes.html#set-types-set-frozenset or ^.a = ['Manzana','Peras','Bananas']
b = ['Manzana','Peras']
print(set(a).symmetric_difference(set(b)))
He returns to us:{'Bananas'}
Another example:a = ['A', 'Y', 'C', 'B', 'L']`
b = ['Y', 'C', 'U', 'L']
print(set(a) ^ set(b))
He returns to us:{'B', 'U', 'A'}
If you use the method difference() or - returns you only elements on the first list but not on the second:a = ['A', 'Y', 'C', 'B', 'L']`
b = ['Y', 'C', 'U', 'L']
print(set(a) - set(b))
He returns to us:{'B', 'A'}
As you see, both must be https://docs.python.org/3/library/stdtypes.html#set-types-set-frozenset Some data are missing such as which database you use, such as storage and extras such data from the database, etc... For these methods to work, you have to be able to transform data into a set (set()).On the other side list(set(queryUno[0]) - set(queryDos[0])) create an object (a list) that contains the difference between the two sets but will not print anything, you need to do something like:print(list(set(queryUno[0]) - set(queryDos[0])))Update including example using https://docs.python.org/3.5/library/sqlite3.html :I will create a database locally (called datos.db) with two tables called stock1 and stock2. Each table has 3 columns that are fruta, kilogramos and cajas. The objective is to compare the two tables using the column frutas and print those fruits that are in stocks1 and not in stocks2:#!/usr/bin/python
# -*- coding: utf-8 -*-
import sqlite3
#Creamos una base de datos llamada datos.db
con = sqlite3.connect('datos.db')
cursor = con.cursor()
#Creamos una tabla llamada stock1 y añadimos 3 filas
cursor.execute('''CREATE TABLE stocks1 (fruta, kilogramos, cajas)''')
items = [('Manzanas','12','4'), ('Peras','10','2'),('Bananas','5','1')]
cursor.executemany('INSERT INTO stocks1 VALUES (?,?,?)', items)
#Creamos una tabla llamada stock1 y añadimos 2 filas
cursor.execute('''CREATE TABLE stocks2 (fruta, kilogramos, cajas)''')
items = [('Manzanas','12','4'), ('Peras','10','2')]
cursor.executemany('INSERT INTO stocks2 VALUES (?,?,?)', items)
con.commit()
con.close()
#Accedemos a nuestra base de datos
con = sqlite3.connect('datos.db');
cursor = con.cursor()
#Extraemos el primer elemento de cada fila de la tabla stocks1
##y lo almacenamos en la lista queryUno
cursor.execute("SELECT * FROM stocks1")
queryUno = set(row[0] for row in cursor)
#Extraemos el primer elemento de cada fila de la tabla stocks2
##y lo almacenamos en la lista queryDos
cursor.execute("SELECT * FROM stocks2")
queryDos = set(row[0] for row in cursor)
#Comparamos las dos tablas
print(queryUno - queryDos)
con.close()
This prints us:>>> ['Bananas']
Greetings.
