Help w/Sum column

Question

The following query will return the last 10 records of a table where the record date falls within the first and last of the current month:
<pre>
SELECT *
FROM (
SELECT p_id, f2, amount, date1
FROM mytable a
WHERE a.date1
BETWEEN TRUNC(SYSDATE,'MM') AND LAST_DAY(SYSDATE)
ORDER BY a.date1 DESC, amount DESC
WHERE rownum <= 10;
</pre>
Now I need to add a column to this query resultset that will have SUM(amount) for ALL the records in the current month (not just the last ten). The idea is that I can hide that last column from my application but still have the field available (total) to add as a footer.
I tried (eliminating the semi-colon after the ten and then appending the following code to the query above:
UNION
SELECT '1','2,SUM(amount), SYSDATE
FROM anothertable b
WHERE b.date2
BETWEEN TRUNC(SYSDATE,'MM') AND LAST_DAY(SYSDATE);
...but all that this does is adds a first record to the recordset with constants "1" and "2" to the first two fields, the desired total sum for the whole month, and the current date. However, I want that sum as another column (even though it may be there ten times), not at the top as another record.
How can I do this?
Thx!

Answer 1

You could just add another subquery, like so:
SELECT *
FROM (
  SELECT p_id, f2, amount, date1,
      ( select sum(amount) from mytable
        where date1 between trunc(sysdate,'mm') and last_day(sysdate)) amount_total
  FROM mytable a
  WHERE a.date1
  BETWEEN TRUNC(SYSDATE,'MM') AND LAST_DAY(SYSDATE)
  ORDER BY a.date1 DESC, amount DESC
WHERE rownum <= 10;