I would like to know how to get a count of the number of rows returned
by a query WITHOUT having to re-run the query.
The query looks something like this:
select dept, num_persons
from(
select dept, num_persons from this_table where.....
UNION ALL
select dept, num_persons from that_table where.....
)
The end report would look like:
Dept Persons
---- -------
A 4
B 5
C 9
TotalDepts 3
I can achieve this result by putting the whole query again in the
sub-query with another UNION ALL and wrapping it in a "select count
from" to get the number of departments, but since we are talking about a
million rows or more, the time needed for the whole query is doubled. Is
there another way of doing this more easily?
