Collect(distinct X))

Question

I have a query that uses the COLLECT() aggregate function. Each item should appear only once in the output (no matter how many rows it's in). I'm running this in two different instances. It works fine in one, which is running "Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - Production". In another, which is running "Oracle Database 10g Enterprise Edition Release 10.2.0.3.0 - 64bit Production", the "DISTINCT" is being ignored, and items appear multiple times.
My actual query is a big messy thing, but this (much smaller) example shows what I mean:
create table stuff (type varchar2(20), item varchar2(20), price number);
insert into stuff (type, item, price) values ('food', 'spam', 1.99);
insert into stuff (type, item, price) values ('food', 'spam', 1.99);
insert into stuff (type, item, price) values ('food', 'spam', 1.99);
insert into stuff (type, item, price) values ('food', 'beans', 0.99);
insert into stuff (type, item, price) values ('food', 'spam', 1.99);
insert into stuff (type, item, price) values ('food', 'spam', 1.99);
insert into stuff (type, item, price) values ('food', 'spam', 1.99);
insert into stuff (type, item, price) values ('food', 'spam', 1.99);
insert into stuff (type, item, price) values ('food', 'bacon', 2.99);
insert into stuff (type, item, price) values ('food', 'spam', 1.99);
insert into stuff (type, item, price) values ('food', 'spam', 1.99);
insert into stuff (type, item, price) values ('food', 'eggs', 3.99);
insert into stuff (type, item, price) values ('clothes', 'shirt', 20);
insert into stuff (type, item, price) values ('electronics', 'camera', 100);
insert into stuff (type, item, price) values ('electronics', 'computer', 600);
select type, collect(distinct item), max(price), min(price)
from stuff
group by type;
drop table stuff;Here's the (correct) result from the 10.2.0.2.0 instance:
clothes
SYSTPYAAXsG1rAW7gQFuAjIUptg==('shirt')
20         20
electronics
SYSTPYAAXsG1rAW7gQFuAjIUptg==('camera', 'computer')
600        100
food
SYSTPYAAXsG1rAW7gQFuAjIUptg==('bacon', 'beans', 'eggs', 'spam')
3.99        .99. . . but here's the nasty failure from 10.2.0.3.0:
clothes
SYSTPYAAQJBD4LhDgQAB/AQBWTg==('shirt')
20         20
electronics
SYSTPYAAQJBD4LhDgQAB/AQBWTg==('camera', 'computer')
600        100
food
SYSTPYAAQJBD4LhDgQAB/AQBWTg==('spam', 'spam', 'spam', 'spam', 'spam', 'bacon', 'spam', 'eggs', 'spam', 'spam', 'spam', 'beans')
3.99        .99Thanks in advance for any insights!
-- John
Edited by: JohnI on Jan 8, 2009 4:48 PM

Answer 1

Funny, but I did not see any evidence that collect(distict X) should work at all.
In the doc: (http://download.oracle.com/docs/cd/B19306_01/server.102/b14200/functions001.htm#sthref962)
"Many (but not all) aggregate functions that take a single argument accept these clauses:
* DISTINCT causes an aggregate function to consider only distinct values of the argument expression.
And then when you look at the functions themselves - the description of "sum" or "avg" shows that usage of distinct is possible, but the description of "collect" does not.
In any case, it looks like a bug that can be reported to Metalink.
BTW. 11.1.0.6 behaves just like 10.2.0.3
Edited by: Chen Shapira on Jan 8, 2009 2:29 PM