Re: [patch] Proposal for \crosstabview in psql - Mailing list pgsql-hackers

I wonder if the business of appending values of multiple columns
separated with spaces is doing us any good.  Why not require that
there's a single column in the cell?  If the user wants to put things
together, they can use format() or just || the fields together.  What
benefit is there to the ' '?  When I ran my first test queries over
pg_class I was surprised about this behavior:

alvherre=# select * from pg_class
alvherre=# \crosstabview relnatts relkind
relnatts |                                                                       r
                                 |                                               t
         |                                                        i
   |                                                                           v
                                  
 

----------+------------------------------------------------------------------------------------------------------------------------------------------------+------------------------------------------------------------------------------------------------+------------------------------------------------------------------------------------------------------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------
    26 | pg_statistic 11 11397 0 10 0 2619 0 15 380 15 2840 t f p 0 f f f f f f f t n 540 1 {alvherre=arwdDxt/alvherre}
(null)                         |
       |
 |       30 | pg_type 11 71 0 10 0 0 0 9 358 9 0 t f p 0 t f f f f f f t n 540 1 {=r/alvherre} (null)
                                    |
            |
      |        3 | pg_user_mapping 11 11633 0 10 0 1418 0 0 0 0 0 t f p 0 t f f f f f f t n 540 1
{alvherre=arwdDxt/alvherre}(null)                             +| pg_toast_2604 99 11642 0 10 0 2830 0 0 0 0 0 t f p 0 f
ff f f f f t n 540 1 (null) (null)    +| pg_amop_opr_fam_index 11 0 0 10 403 2654 0 5 688 0 0 f f p 0 f f f f f f f t n
00 (null) (null)                +| pg_group 11 11661 0 10 0 11660 0 0 0 0 0 f f p 0 f f t f f f f t n 0 0 {=r/alvherre}
(null)                                                         +
 


I'm tempted to rip that out, unless you have a reason not to.

In fact, I think even the grouping of values of multiple rows with \n is
not terribly great either.  Why not just require people to group the
values beforehand?  You can use "string_agg(column, E'\n')" to get the
same behavior, plus you can do other things such as sum() etc.

-- 
Álvaro Herrera                http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services