Question

I’m testing that the latest date in several tables all match each other in oracle. The SQL I came up with looks like:

select ICEAG.process_month
from (
    select *
    from (
        select process_month
        from TABLE1
        group by process_month
        order by process_month desc
    )
    where rownum <=1
) ICEAG
join (
    select *
    from (
        select process_month
        from TABLETWO
        group by process_month
        order by process_month desc
    )
    where rownum <=1
) GAI on (ICEAG.process_month = GAI.process_month)

This works but I need to check about 12 tables. Should I just keep joining more subqueries, or is there a better way?

Answer 1

SELECT COUNT(*) FROM (
(SELECT MAX(process_month) FROM TABLE1)
  UNION
(SELECT MAX(process_month) FROM TABLE2)
  UNION
(SELECT MAX(process_month) FROM TABLE3)
);

When result is > 1, then one of the tables has different last process_month.