Re: [patch] Proposal for \crosstabview in psql

  Hi,

Here's an updated patch improving on how the horizontal and vertical
headers can be sorted.

The discussion upthread went into how it was desirable
to have independant sorts for these headers, possibly driven
by another column, in addition to the query's ORDER BY.

Thus the options now accepted are:

\crosstabview [ [-|+]colV[:scolV] [-|+]colH[:scolH]  [colG1[,colG2...]] ]

The optional scolV/scolH columns drive sorts for respectively
colV/colH (colV:scolV somehow means SELECT colV from... order by scolV)

colG1,... in 3rd arg indicate the columns whose contents form the grid
cells, the typical use case being that there's only one such column.
By default it's all columns minus colV and colH.

For example,

SELECT
  cust_id,
  cust_name,
  cust_date,
  date_part('month, sales_date),
  to_char(sales_date, 'Mon') as month,
  amount
FROM sales_view
WHERE [predicates]
[ORDER BY ...]

If we want to look at <amount> in a grid with months names across, sorted
by month number, and customer name in the vertical header, sorted by date of
acquisition, we could do this:

\crosstabview +cust_name:cust_date +5:4 amount

or letting the vertical header being sorted by the query's ORDER BY,
and the horizontal header same as above:

\crosstabview cust_name +5:4 amount

or sorting vertically by name, if it happens that the ORDER BY is missing or
is on something else:

\crosstabview +cust_name +5:4 amount

Best regards,
--
Daniel Vérité
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