Grouping by date range

[Mat]

Hi,
I have a table with two column, date and data
I would like to do a set of queries to generate statistics on the data,
such as count(data) for month blocks and year blocks. What is the best
way to accomplish this?
dd/mm/yy
date | data
---------------
01/01/01| 123
01/01/01| abc
02/01/01| def
03/03/01| hij

SOME QUERY ....

Year | Count
-------------
01 | 3

I can see how to group by day - but how do i go about decreasing the
precision down to months/years.

Thanks...
---------------------------(end of broadcast)---------------------------
TIP 8: explain analyze is your friend

[Ron Johnson]

On Wed, 2003-08-20 at 14:51, Tom Lane wrote:

Bruno Wolff III <br***@wolff.to > writes:

On Wed, Aug 20, 2003 at 13:44:59 -0500,
Ron Johnson <ro***********@ cox.net> wrote:

The GROUP BY does implicit sorting, so an ORDER BY on the exact same
column(s) as the GROUP BY is redundant.

That is an implementation detail, not a promise. With hashed aggregates
in 7.4, you might find this isn't true.

s/might/will/

From 7.3.3, where the records were randomly inserted; note how
GROUP BY acts like I described:

test1=# select f, count(*)
test1-# from t
test1-# group by f;
f | count
---+-------
1 | 3
2 | 5
4 | 4
(3 rows)

The new 7.4 attitude is *really* good to know, because, otherwise,
all our reports would break!
--
-----------------------------------------------------------------
Ron Johnson, Jr. ro***********@c ox.net
Jefferson, LA USA

"Fair is where you take your cows to be judged."
Unknown
---------------------------(end of broadcast)---------------------------
TIP 9: the planner will ignore your desire to choose an index scan if your
joining column's datatypes do not match