Select within a select in Oracle


I  have seen the code before where partition by is used in an Oracle Query to get row_num and there is another query concatanated to it to get other columns within the table where row_num = 1. Can someone give me the syntax for this?  I  believe it looks something like this:

Select row_number() over (partition by member_id ORDER BY date_entered DESC) rownum FROM
 Select   member_id
           , claim
          , date_entered
where rownum = 1;
moriniaAdvanced Analytics AnalystAsked:
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The query you posted makes no sense, try posting your requirements clearly.

Otherwise check: Oracle® Database SQL Language Reference
11g Release 2 (11.2) Analytical Functions
johnsoneSenior Oracle DBACommented:
Some sample data and expected results would be helpful.  Looking purely at the query, I would say you are looking for this:

SELECT member_id, 
FROM   (SELECT member_id, 
                 over ( 
                   PARTITION BY member_id 
                   ORDER BY date_entered DESC) rn 
        FROM   tablea) 
WHERE  rn = 1; 

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However that is a guess.  If that is not what you are looking for, then we need a better understand of what you are trying to accomplish.

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