PostgreSQL bug in SELECT DISTINCT

When I execute the following query:
SELECT DISTINCT title FROM division ORDER BY UPPER(title);
I get:
ERROR: For SELECT DISTINCT, ORDER BY expressions must appear in target list
If I remove DISTINCT, the query works fine.
Is this illegal or a known bug?

Illegal. I believe that allowing any function call in the "order by"
clause is an extension to SQL9x, so feel lucky that you can do it at all
;)

However,

SELECT T FROM (SELECT DISTINCT title FROM division) AS T ORDER BY
UPPER(T);

seems to work in 7.1 (but not in earlier releases). This give PostgreSQL
a chance to hold an intermediate result to sort in a second pass.

- Thomas

"J.R. Onyschak" <jonyschak@nvisia.com> writes:

When I execute the following query:
SELECT DISTINCT title FROM division ORDER BY UPPER(title);

I get:
ERROR: For SELECT DISTINCT, ORDER BY expressions must appear in target list

If I remove DISTINCT, the query works fine.

Is this illegal or a known bug?

This is not a bug, but an intentional restriction to prevent ill-defined
query results. Why don't you just "ORDER BY title"?

regards, tom lane

Tom Lane wrote:

"J.R. Onyschak" <jonyschak@nvisia.com> writes:

When I execute the following query:
SELECT DISTINCT title FROM division ORDER BY UPPER(title);

I get:
ERROR: For SELECT DISTINCT, ORDER BY expressions must appear in target list

If I remove DISTINCT, the query works fine.

Is this illegal or a known bug?

This is not a bug, but an intentional restriction to prevent ill-defined
query results. Why don't you just "ORDER BY title"?

regards, tom lane

I can't/don't want to "ORDER BY title" because the title might be
entered as upper case or lower case. If we had divisions with titles
Transportation, parks, and Education. I would like to display the
results alphabetical regardless of capitalization. I know this example
is a little contrived because all divisions should be capitalized, but
we have a number of "objects" backed by tables that have a title column
that we order by and some of them have a high chance of having mixed
capitalization. I can understand the prevention of ill-defined query
results, but is PostgreSql being too restrictive? I am ordering by a
column in the select clause, I am just using a function on that column.

Thanks for the great product. It truely has been fun using
PostgreSql.Very robust, very easy to use.

Thank you for your help,
jr

P.S. I don't mean for this to sound whiny, but I encounterd this in
porting a project from using Oracle to PostgreSql, so I know that Oracle
supports it and other people might run into this problem.
P.P.S. Where can I locate a copy of the latest SQL spec?

Thomas Lockhart wrote:

When I execute the following query:
SELECT DISTINCT title FROM division ORDER BY UPPER(title);
I get:
ERROR: For SELECT DISTINCT, ORDER BY expressions must appear in target list
If I remove DISTINCT, the query works fine.
Is this illegal or a known bug?

Illegal. I believe that allowing any function call in the "order by"
clause is an extension to SQL9x, so feel lucky that you can do it at all
;)

Where can I look at a copy of the SQL spec? I've tried to locate it
online, but haven't been able to find it.

However,

SELECT T FROM (SELECT DISTINCT title FROM division) AS T ORDER BY
UPPER(T);

seems to work in 7.1 (but not in earlier releases). This give PostgreSQL
a chance to hold an intermediate result to sort in a second pass.

- Thomas

That's interesting. I remember that, but I don't think I should rely on
it because I am trying to keep our SQL code portable across databases.
(We've already made once change and might have to do another)

Thanks for your time,
J.R.