Question

I’m trying to return 7 events from a table, from todays date, and have them in date order:

SELECT ID
FROM table
 where ID in (select ID from table
where DATEFIELD >= trunc(sysdate)
order by DATEFIELD ASC)
and rownum <= 7

If I remove the ‘order by’ it returns the IDs just fine and the query works, but it’s not in the right order. Would appreciate any help with this since I can’t seem to figure out what I’m doing wrong!

(edit) for clarification, I was using this before, and the order returned was really out:

select ID
from TABLE
where DATEFIELD >= trunc(sysdate)
and rownum <= 7
order by DATEFIELD 

Thanks

Answer 1

The values for the ROWNUM “function” are applied before the ORDER BY is processed. That why it doesn’t work the way you used it (See the manual for a similar explanation)

When limiting a query using ROWNUM and an ORDER BY is involved, the ordering must be done in an inner select and the limit must be applied in the outer select:

select *
from (
  select *
  from table
  where datefield >= trunc(sysdate)
  order by datefield ASC
)
where rownum <= 7