**id    food_1  city_1  food_2  city_2**

1   cake    paris   cake    paris

2   pepsi   london  pepsi   london

3   NULL    delhi   NULL    delhi

4   chicken berlin  chicken berlin

5   NULL    NULL    NULL    NULL

6   wine    NULL    NULL    NULL

7   NULL    cologne NULL    tokyo

8   egg mumbai  egg mumbai

SELECT
id
FROM food_city
WHERE food_1 <> food_2 OR city_1 <> city_2