[datatable-help] changing data.table by-without-by syntax to require a "by"

[Eduard Antonyan]

By that you mean current behavior? You'd get current behavior by explicitly
specifying the appropriate "by" (i.e. "by" equal to the key).

Btw, I'm trying to understand SQL CROSS APPLY vs JOIN using
http://explainextended.com/2009/07/16/inner-join-vs-cross-apply/, and I
can't figure out how by-without-by (or with by-with-by for that matter:) )
helps with e.g. the first example there:

"We table table1 and table2. table1 has a column called rowcount.

For each row from table1 we need to select first rowcount rows from table2,
ordered by table2.id"




On Wed, Apr 24, 2013 at 4:01 PM, Matthew Dowle <mdowle at mdowle.plus.com>wrote:

> But then what would be analogous to CROSS APPLY in SQL?
>
> > I'd agree with Eduard, although it's probably too late to change behavior
> > now.  Maybe for data.table.2?  Eduard's proposal seems more closely
> > aligned with SQL behavior as well (SELECT/JOIN, then GROUP, but only if
> > requested).
> >
> > S.
> >
> >> Date: Mon, 22 Apr 2013 08:17:59 -0700
> >> From: eduard.antonyan at gmail.com
> >> To: datatable-help at lists.r-forge.r-project.org
> >> Subject: Re: [datatable-help] changing data.table by-without-by
> >> syntax       to      require a "by"
> >>
> >> I think you're missing the point Michael. Just because it's possible to
> >> do it
> >> the way it's done now, doesn't mean that's the best way, as I've tried
> >> to
> >> argue in the OP. I don't think you've addressed the issue of unnecessary
> >> complexity pointed out in OP.
> >>
> >>
> >>
> >> --
> >> View this message in context:
> >>
> http://r.789695.n4.nabble.com/changing-data-table-by-without-by-syntax-to-require-a-by-tp4664770p4664990.html
> >> Sent from the datatable-help mailing list archive at Nabble.com.
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> >>
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