Обсуждение: Cheers for DISTINCT ON
I just wanted to give my cheers for DISTINCT ON. It is a great feature, I've just found a really good use for it. I am just wondering why it didn't make it into the standards. On a slightly unrelated note, I had the opportunity to work with EQUEL for a short period of time some 15 years ago before I started getting famililar with SQL. I clearly remember the disappointment/surprise I felt as I was struggling to translate some of the constructs I used with EQUEL into SQL. At that time, I thought that (the by then defunct) EQUEL was much more expressive/intuitive/flexible/easier-to-use than SQL. I've been wondering ever since why the worse so often gets the upper-hand over the better. (I am obviously having a hard time "growing-up" :-) ) Cheers, Peter
On Mon, Jan 07, 2008 at 05:02:27PM +0100, Peter Kovacs wrote: > I just wanted to give my cheers for DISTINCT ON. It is a great > feature, I've just found a really good use for it. I am just wondering > why it didn't make it into the standards. Likely because neither Oracle Corp nor IBM nor (at the time, I guess) Sybase had an implementation they were willing to spend enough time promoting. > wondering ever since why the worse so often gets the upper-hand over > the better. (I am obviously having a hard time "growing-up" :-) ) There is a long history in the computing literature on this, but the best explanation is probably still Richard Gabriel's 'The Rise of "Worse is Better"': <http://www.jwz.org/doc/worse-is-better.html>. Note that Gabriel himself is of two minds about that paper: <http://www.dreamsongs.com/WorseIsBetter.html>. I still think it's worth reading. Just about everything I've ever written or said turned out to be wrong in some sense, but it was still usually the result of the best argument I could make at the time. A
Peter Kovacs wrote: > I just wanted to give my cheers for DISTINCT ON. It is a great > feature, I've just found a really good use for it. I am just wondering > why it didn't make it into the standards. > > On a slightly unrelated note, I had the opportunity to work with EQUEL > for a short period of time some 15 years ago before I started getting > famililar with SQL. I clearly remember the disappointment/surprise I > felt as I was struggling to translate some of the constructs I used > with EQUEL into SQL. At that time, I thought that (the by then > defunct) EQUEL was much more > expressive/intuitive/flexible/easier-to-use than SQL. I've been > wondering ever since why the worse so often gets the upper-hand over > the better. (I am obviously having a hard time "growing-up" :-) ) As a former EQUEL user myself I had the same reaction to SQL. I think EQUEL and SQL both have strengths, but I think SQL subqueries and the cleaner handling of group aggregates makes SQL more useful in a variety of ways. -- Bruce Momjian <bruce@momjian.us> http://momjian.us EnterpriseDB http://postgres.enterprisedb.com + If your life is a hard drive, Christ can be your backup. +
ajs@crankycanuck.ca (Andrew Sullivan) writes: > On Mon, Jan 07, 2008 at 05:02:27PM +0100, Peter Kovacs wrote: >> I just wanted to give my cheers for DISTINCT ON. It is a great >> feature, I've just found a really good use for it. I am just wondering >> why it didn't make it into the standards. > > Likely because neither Oracle Corp nor IBM nor (at the time, I guess) Sybase > had an implementation they were willing to spend enough time promoting. > >> wondering ever since why the worse so often gets the upper-hand over >> the better. (I am obviously having a hard time "growing-up" :-) ) > > There is a long history in the computing literature on this, but the best > explanation is probably still Richard Gabriel's 'The Rise of "Worse is > Better"': <http://www.jwz.org/doc/worse-is-better.html>. Note that Gabriel > himself is of two minds about that paper: > <http://www.dreamsongs.com/WorseIsBetter.html>. I still think it's worth > reading. Just about everything I've ever written or said turned out to be > wrong in some sense, but it was still usually the result of the best > argument I could make at the time. I have heard that Gabriel has, at different conferences at different times, taken and argued opposite positions on this; he has both argued "Worse is Better" and that "Worse isn't Better." Another view is "Good Enough is Better." http://www.mired.org/home/mwm/good-enough.html -- "cbbrowne","@","cbbrowne.com" http://www3.sympatico.ca/cbbrowne/advocacy.html "Generally in war the best policy is to take a state intact; to ruin it is inferior to this. To win one hundred victories in one hundred battles is not the acme of skill. To subdue the enemy without fighting is the acme of skill." -- Sun-Tzu, The Art of War
bruce@momjian.us (Bruce Momjian) writes:
> Peter Kovacs wrote:
>> I just wanted to give my cheers for DISTINCT ON. It is a great
>> feature, I've just found a really good use for it. I am just wondering
>> why it didn't make it into the standards.
>>
>> On a slightly unrelated note, I had the opportunity to work with EQUEL
>> for a short period of time some 15 years ago before I started getting
>> famililar with SQL. I clearly remember the disappointment/surprise I
>> felt as I was struggling to translate some of the constructs I used
>> with EQUEL into SQL. At that time, I thought that (the by then
>> defunct) EQUEL was much more
>> expressive/intuitive/flexible/easier-to-use than SQL. I've been
>> wondering ever since why the worse so often gets the upper-hand over
>> the better. (I am obviously having a hard time "growing-up" :-) )
>
> As a former EQUEL user myself I had the same reaction to SQL. I think
> EQUEL and SQL both have strengths, but I think SQL subqueries and the
> cleaner handling of group aggregates makes SQL more useful in a variety
> of ways.
If EQUEL had continued to evolve, might it not have improved in these
ways?
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On Mon, Jan 07, 2008 at 12:51:19PM -0500, Chris Browne wrote: > I have heard that Gabriel has, at different conferences at different > times, taken and argued opposite positions on this; he has both argued > "Worse is Better" and that "Worse isn't Better." Yes. That history is actually outlined by him in the second link I posted. A