How to have org-babel treat the first line of a table result as a header?

Question

I'm dealing with a trivial shell script that invokes the mysql binary on a remote server, and having org-babel capture its results as a table.

With sensitive information scrubbed, the source block resembles

#+BEGIN_SRC sh :results value table
#!/bin/sh
ssh remote.host 'mysql db -e "SELECT foo,bar,baz FROM stuff"'
#+END_SRC

and its result is formatted as tab-separated values, the first row of which is a header naming the columns:

foo^Ibar^Ibaz
value^Ivalue^Ivalue
value^Ivalue^Ivalue
⋮

Org-babel correctly interprets this result as a table. What it doesn't do, and I haven't been able to figure out how to get it to do, is treat the first row of this result as a header. More specifically, I want there to be an hline automatically inserted after the first row, so that I can pass just the values to downstream code blocks, without having to have the code in them explicitly filter out the first line.

I'm (almost) sure there is a fairly trivial way to do this, because I've seen examples in other questions on Emacs SE of code block result tables which (appear to be) automatically formatted the way I want mine to be. I just haven't been able to find how to do it for myself in the org-babel documentation.

Answer 1

A rather brute force way is to define a post-processing function to add an hline after the first row.

#+name: addhdr
#+begin_src emacs-lisp :var tbl=""
(cons (car tbl) (cons 'hline (cdr tbl)))
#+end_src

Then call that function as postprocessing using the :post header:

#+begin_src elisp :results value table :post addhdr(*this*)
'((a b c d) (1 2 3 4) (a b c d) (1 2 3 4))
#+end_src

#+RESULTS:
| a | b | c | d |
|---+---+---+---|
| 1 | 2 | 3 | 4 |
| a | b | c | d |
| 1 | 2 | 3 | 4 |

Note that the addhdr function lacks checks for empty tables.