Re: [patch] Proposal for \rotate in psql

Pavel Stehule wrote:

> my comments:
>
> 1. I don't understand why you are use two methods for sorting columns
> (qsort, and query with ORDER BY)

qsort (with strcmp as the comparator) is only used to determine the
set of distinct values for the vertical and horizontal headers.
In fact this is just to allow the use of bsearch() when doing that
instead of a slower sequential search.

Once the values for the horizontal headers are known, they
are passed to the server for sorting with server-side semantics
according to their type. The order will differ from qsort/strcmp
found as the comparison semantics are different.

The values for the vertical header are not sorted server-side
because we keep the order of the query for displaying
top to bottom.
In the typical use case , it will have ORDER BY 1[,2] possibly
with one/two DESC qualifiers.

> 2. Data column are not well aligned - numbers are aligned as text

Yes. I'll look shortly into fixing that.

Best regards,
--
Daniel Vérité
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