* wishful thinking: using SQL to process tables. in the meantime, use R
@ 2016-07-21 1:13 dmg
2016-07-21 17:35 ` Thierry Banel
0 siblings, 1 reply; 2+ messages in thread
From: dmg @ 2016-07-21 1:13 UTC (permalink / raw)
To: emacs-orgmode
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Hi everybody,
I was wondering if there was a way to join two tables given
a common column. I searched but found nothing.
it would be awesome to be able to process tables in SQLITE.
something like this:
#+BEGIN_SRC sqlite :var a=table1 b=table2 :colnames yes
select * from $a join $b using column;
#+END_SRC
I think it is not that hard. The infrastructure is there already.
It is just a matter of creating temp tables (this is the major part missing
which implies making a create statement from the table, but given
that sqlite is very type agnostic, it might not be hard),
load them from the CSV files
the execute the block. A db parameter might be needed
for a scratch database file, but it could be a temporary one if
none is provided.
But in the meantime, it occurred to me, it is simple in R to do the join
and might be useful to others:
#+BEGIN_SRC R :var a=table1 b=table2 :results value :colnames yes
merge(a,b,by.x="column")
#+END_SRC
merge can do left joins, right joins, full joins, joins,
https://stat.ethz.ch/R-manual/R-devel/library/base/html/merge.html
but there is nothing like the power of SQL to process tables, though.
--
--dmg
---
Daniel M. German
http://turingmachine.org
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* Re: wishful thinking: using SQL to process tables. in the meantime, use R
2016-07-21 1:13 wishful thinking: using SQL to process tables. in the meantime, use R dmg
@ 2016-07-21 17:35 ` Thierry Banel
0 siblings, 0 replies; 2+ messages in thread
From: Thierry Banel @ 2016-07-21 17:35 UTC (permalink / raw)
To: emacs-orgmode
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2016-07-21 1:13 wishful thinking: using SQL to process tables. in the meantime, use R dmg
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