load external command in the same split after repeating it - vim

Question

I want to load some text coming from a command line command into a new vim split. I got this working but if I run the command again it keeps opening new splits.
What I want to achieve is getting this into the same split. How can I do this?
nnoremap <leader>q :execute 'new <bar> 0read ! bq query --dry_run --use_legacy_sql=false < ' expand('%')<cr>

Answer 1

I would suggest using the preview window via the :pedit command.
nnoremap <leader>q :execute 'pedit <bar> wincmd p <bar> 0read ! bq query --dry_run --use_legacy_sql=false < ' expand('%')<cr>
However we can do even better by doing the following:
Making a "query" operator using g# and 'opfunc'
A query command (feels very vim-like to do so)
Using stdin instead of a filename
Example:
function! s:query(str)
pedit [query]
wincmd p
setlocal buftype=nofile
setlocal bufhidden=wipe
setlocal noswapfile
%delete _
call setline(1, systemlist('awk 1', a:str))
endfunction
function! s:query_op(type, ...)
let selection = &selection
let &selection = 'inclusive'
let reg = ##
if a:0
normal! gvy
elseif a:type == 'line'
normal! '[V']y
else
normal! `[v`]y
endif
call s:query(##)
let &selection = selection
let ## = reg
endfunction
command! -range=% Query call s:query(join(getline(<line1>, <line2>), "\n"))
nnoremap \qq :.,.+<c-r>=v:count<cr>Query<cr>
nnoremap \q :set opfunc=<SID>query_op<cr>g#
xnoremap \q :<c-u>call <SID>query_op(visualmode(), 1)<cr>
Note: I am using awk 1 as my "query" command. Change to meet your needs.
For more help see:
:h :pedit
:h :windcmd
:h operator
:h g#
:h 'opfunc'
:h systemlist()