Question

I have this table

rss_user. You see account name, application name and application type.

with
RSS_USER_NAME RSS_NAME RSS_TYPE

example data

[e-mail]   webapp4     webapps
[e-mail]   webapp6     webapps
[e-mail]   mswin3      windows
[e-mail]   mswin2      windows
[e-mail] mswin2      windows
[e-mail] webapp6     webapps

I wish to get one random account from the combination of rss_name and rss_type. Every combination of rss_name and rss_type should have one random account.

current code. Completly useless 🙁

SELECT *
  FROM (  SELECT    'SYNC rss_user WITH rss_user_name = "'
             || RSS_USER_NAME
             || '" , rss_name = "'
             || RSS_NAME
             || '" , rss_type = "'
             || RSS_TYPE
             || '";'
        FROM rss_user
    ORDER BY DBMS_RANDOM.VALUE)
 WHERE ROWNUM = 1

result:

SYNC rss_user WITH rss_user_name = "[e-mail]" , rss_name = "webapp4" , rss_type = "webapps";

Answer 1

Here is an approach:

SELECT *
  FROM (SELECT    'SYNC rss_user WITH rss_user_name = "'
             || RSS_USER_NAME
             || '" , rss_name = "'
             || RSS_NAME
             || '" , rss_type = "'
             || RSS_TYPE
             || '";',
                 seqnum = row_number() over (partition by rss_name, rss_type order by dbms_random.value)
         FROM rss_user
        ) t
 WHERE seqnum = 1

That is, use row_number() and dbms_random.value with each other to select a random row.