Dynamic query in sql server

Question

I have faced a interview question.

 

Input

 

Id Country Amount

1 India         1000

2 US             2000

3  Dubai        30000

 

Output

 

Id Country Amount Currency

1 India    1000         Rupee

2 US      2000          Dollor

3 Dubai    30000      Dhiram

 

I wrote a query with case statement for above three records, he asked me to write a dynamic query for lakhs of records. How can i acheive it?

 

 

Thanks in advance.