Full-stack dev quiz question #5

Full-stack dev quiz question #5

The fifth question in the quiz for a full-stack developer checks basic knowledge of SQL.

Correct answer for the fourth question is published.

Analyze the following SQL script created for SQL Server:

create table COUNTRIES (
   Ctr_Id int,
   Ctr_Name varchar(255)
)
GO

create table USERS (
   Usr_Id int,
   Usr_Ctr_Id int,
   Usr_Name varchar(255)
)
GO

insert into COUNTRIES (Ctr_Id, Ctr_Name)
values (1, 'Poland'), (2, 'Germany'), (3, 'India'), (4, 'Canada')

insert into USERS (Usr_Id, Usr_Ctr_Id, Usr_Name)
values (1, 2, 'Johannes'), (2, 2, 'Aldona'), (3, 3, 'Rahit')

What is the result of this query:

select Ctr_Name, count(1)
from COUNTRIES
        left join USERS on Ctr_Id = Usr_Ctr_Id
group by Ctr_Name
order by Ctr_Name

Choose one:

1. Canada	1
   Germany	2
   India	1
   Poland	1

2. Germany	2
   India	1
   Poland	0
   Canada	0

3. Canada	0
   Germany	2
   India	1
   Poland	0

4. Germany	2
   India	1

5. Germany	2
   India	1
   null	0
   null	0

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The correct answer is a.