Question

I have a situation. How can I extract AppId that has only taken C++. and no other course.
Sample data is shown below

AppID  | Course
---------------
101    |  C++
101    | Data Structure
100    | C++.
201    | Analysis of Alogrithm
201    | Data Structure

and so on

Here is the dummy SQL

DROP TABLE #app

CREATE TABLE #app (AppID  int, Course nvarchar(50))
INSERT INTO #app 
VALUES(101,'C++'),
(101  ,'Data Structure'),
(100  ,'C++'),
(201  ,'Analysis of Alogrithm'),
(201  ,'Data Structure')

Select AppId,Course From #app

Answer 1

I think this will work

select AppId from #app a
where 
AppId in (select AppId from #app where Course='C++') and
1 = (select count(course) from #app where AppId=a.AppId)