SQL - select rows that have the same value in two columns

Question

The solution to the topic is evading me.

I have a table looking like (beyond other fields that have nothing to do with my question):

NAME,CARDNUMBER,MEMBERTY

Answer 1

You can use exists for this:

select * 
from yourtable y
where exists (
  select 1
  from yourtable y2 
  where y.name <> y2.name
    and y.cardnumber = y2.cardnumber
    and y.membertype = y2.membertype)

• SQL Fiddle Demo