DISTINCT within aggregates.

Hi,

I have PG 6.4 which does not appear to support DISTINCT with aggregates.

Here's an example with the following table:

key|numero
---+-----
  1|one
  2|two
  3|three
  4|one
  4|four
  2|one
(6 rows)

brecard10=> select count(numero) from test;
count
-----
    6
(1 row)

brecard10=>  select count(numero) from test group by value;
count
-----
    1
    3
    1
    1
(4 rows)

brecard10=> select count(distinct numero) from test group by value;
ERROR:  parser: Syntax error at or near "distinct"

I want to be able to count how many DISTINCT 'numero' entries there are in
test (i.e 4).
The first statement is a simple count.
The second uses a group which does indeed tell us that there are four
different 'numero's but does not return a unique count.
The last statement is the statement to use (at least according to my SQL
handbook - Bowman et al.) but is not supported by PG 6.4.

Has anybody found a workaround?

cheers,

Stuart.


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| Stuart Rison            | Ludwig Institute for Cancer Research |
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