a sql query from oracle database

Question

I have two columns(column1, column2) in my oracle database table named as demo. I want to select same column1 having different column2.

SQL> select * from demo;

column1 | column2
--------|--------
A       | 10           
A       | 20
A       | 30
A       | 30

I want the following output with count(*):

column1 | column2
--------|--------
A       | 10           
A       | 20

How can i do this? Any help is much appreciated

Answer 1

Try:

select column1, column2
from myTable 
group by column1, column2
having count(*) = 1