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From James Fang <jfang...@ucr.edu>
Subject Re: Postgres Aggregation Function - Discussion
Date Wed, 18 Nov 2015 22:06:09 GMT
Just wondering if anyone has a response on this discussion?

Thanks,
James

On Mon, Nov 9, 2015 at 2:11 PM, James Fang <jfang003@ucr.edu> wrote:

> The following functions that I am asking about are from
> http://www.postgresql.org/docs/9.4/static/functions-aggregate.html
>
> The following google doc contains a spreadsheet of all the current
> aggregation functions that exist in AQL and SQL. The colored portions will
> be the portions that I wish to discuss. I assumed that AQL returns null if
> at least 1 of the results in the aggregation is null while SQL ignores the
> tuple if it is null.
>
> https://docs.google.com/document/d/1l9QtRAB7H3yzP3976livpKzJZHVJlPdvDrjlm2YCsM0/edit?usp=sharing
>
> Questions:
> 1) Do we need array_agg, this function just groups up the results together
> into one array as output. If so, do we want a scalar version or aggregate
> version?
> 2) For bitwise-or and bitwise-and, I have implemented a sql aggregate
> version. Do we want a AQL aggregate version as well? Do you think that we
> should implement this as a scalar or as an aggregation?
> 3) For boolean-or and boolean and, we current have an existing scalar
> version for AQL. Do we need a scalar version for SQL? Should we implement a
> aggregate version of these boolean functions?
> 4) Do we need a json_agg function? I do not think so because all the data
> is returned in json format. If you have a different answer, let me know.
> 5) For string_agg, we currently have a scalar version for AQL known as
> string-join. Do we need a SQL version?
>

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