MySQL temp table example for missing values

gistfile1.txt

create table pantry(name varchar(50), quantity int);

insert into pantry values('soup', 10), ('celery', 5), ('crackers', 2);

create temporary table shopping_list(name varchar(50));

insert into shopping_list values ('soup'), ('onion'), ('celery');

select a.name, ifnull(b.quantity, 0) as quantity
from shopping_list a
left join pantry b on a.name = b.name;

+--------+----------+
| name   | quantity |
+--------+----------+
| soup   |       10 |
| onion  |        0 |
| celery |        5 |
+--------+----------+
3 rows in set (0.00 sec)

drop table shopping_list;