Select three rows when two of them need to be unique (SQL)

Question

First of all I am using Oracle 10g Express

So there are three columns I want to select:

[domain_name] [index_path] [collection_name]

Now there are two columns that I want to be unique:

[domain_name] [index_path]

So my issue is how do I basically:

select unique domain_name, index_path from TABLENAMEHERE

while also selecting the column [collection_name]

Answer 1

Just replace unique with distinct in your query.

Oh...

Then it should be like this:

select [domain_name], [index_path], min([collection_name]) 
from TABLENAMEHERE
group by [domain_name], [index_path]

Answer 2

You can group by the domain_name and index_path and include ONE (min or max) value of collection_name per group.

Answer 3

If there are multiple rows for some combinations of domain_name, index_path then what value of collection_name would you want to see from those rows? If you don't mind which value then do:

SELECT domain_name, index_path, MIN(collection_name) collection_name
FROM TABLENAMEHERE
GROUP BY domain_name, index_path;

Answer 4

select domain_name, index_path, collection_name
  from my_table outr
       inner join 
         (select domain_name, index_path, collection_name, 
                 max(gen_timestamp) 
                    over (partition by domain_name, index_path) gen_timestamp
            from my_table) innr
 where outr.domain_name = innr.domain_name
   and outr.index_path  = innr.index_path
   and outr.collection_name = innr.collection_name
   and outr.gen_timestamp   = innr.gen_timestamp