Thread: Re: Book - SQL Aggregates

> %--
> %--> Dear sir,
> %--> 
> %--> Just one remark for your book :
> %--> in your chapter "SQL Aggregates", it is interessant perhaps if you
> %--> say if COUNT(DISTINCT ...) for example is supported. 
> %--> 
> %--> mb
> %--> 
> %--
> %--It isn't supported.
> %--
> 
> Sorry, I just want to say "It is not supported" obviously. I think, it is 
> important to say it, because I search for my mistake a little bit before
> finding the answer in the FAQ.

CC to hackers.

The best way to do that is to display a mess to the user when they try
COUNT(DISTINCT...).   That makes it easy because they see it as soon as
they try it.  No hunting around, but I am not sure how to do that in the
grammer because we don't find out about aggregates until later.


--  Bruce Momjian                        |  http://www.op.net/~candle maillist@candle.pha.pa.us            |  (610)
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Bruce Momjian <pgman@candle.pha.pa.us> writes:
> The best way to do that is to display a mess to the user when they try
> COUNT(DISTINCT...).   That makes it easy because they see it as soon as
> they try it.

I was actually thinking about trying to implement aggregate(DISTINCT ...),
or failing that, at least understand why it's hard ;-)

At the very least I think I can manage an explicit "DISTINCT not supported"
error message from the parser.  Will take this as a TODO item.
        regards, tom lane