Thanks everyone for answering. Apparently my question was not clear enough.
I want something like this:
select col1, col2,col3, col4
from table1
where
col1 =col1 and
col2 = col2 and
col3 = col3
order by col4
But if I run this query I get all the records in the table and not just the (double) ones with the same columns.
TIA
Joost