Interesting TSQL Question

Check the below TSQL Example involving NULL. What is the result for below three queries

Tested on SQL 2012 Setup

Create TABLE Test1

(Id           int,

 Score int not null)

Create TABLE Test2

(Id           int,

 Score2       int not null)

 insert into Test1(Id, Score) VALUES (NULL,10),(10,100),(20,200)

 insert into Test2(Id, Score2) VALUES (NULL,11),(10,110),(20,220)

Case #1 

 Select * from  Test1 JOIN Test2

 ON Test1.Id = Test2.Id

Case #2 

 Select * from  Test1 LEFT OUTER JOIN Test2

 ON Test1.Id = Test2.Id

Case #3

 Select * from  Test1 LEFT OUTER JOIN Test2

 ON Test1.Id = Test2.Id

 ORDER BY Test1.Id DESC

Results are

Happy Learning!!!