Re: [patch] Proposal for \rotate in psql

2015-12-14 23:09 GMT+01:00 Daniel Verite <daniel(at)manitou-mail(dot)org>:

> Pavel Stehule wrote:
>
> > postgres=# \crosstabview 4 +month label
> >
> > Maybe using optional int order column instead label is better - then you
> can
> > do sort on client side
> >
> > so the syntax can be "\crosstabview VCol [+/-]HCol [[+-]HOrderCol]
>
> In the meantime I've followed a different idea: allowing the
> vertical header to be sorted too, still server-side.
>
> That's because to me, the first impulse for a user noticing that
> it's not sorted vertically would be to write
> \crosstabview +customer month
> rather than figure out the
> \crosstabview customer +month_number month_name
> invocation.
> But both ways aren't even mutually exclusive. We could support
> \crosstabview [+|-]colV[:labelV] [+|-]colH[:labelH]
> it's more complicated to understand, but not harder to implement.
>
> Also, a non-zero FETCH_COUNT is supported by this version of the patch,
> if the first internal FETCH retrieves less than FETCH_COUNT rows.
> Otherwise a specific error is emitted.
>
> Also there are minor changes in arguments and callers following
> recent code changes for \o
>
> Trying to crosstab with 10k+ distinct values vertically, I've noticed
> that the current code is too slow, spending too much time
> sorting. I'm currently replacing its simple arrays of distinct values
> with AVL binary trees, which I expect to be much more efficient for
> this.
>

I played with last version and it is looking well. I have only one notice,
but it is subjective - so can be ignored if you don't like it.

The symbol 'X' in two column mode should be centred - now it is aligned to
left, what is not nice. For unicode line style I prefer some unicode symbol
- your chr(10003) is nice.

Regards

Pavel

>
> Best regards,
> --
> Daniel Vérité
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> Twitter: @DanielVerite
>