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* Re: psql: print values and return the COUNT(*) value to bash?
@ 2025-12-29 16:40 Vincent Veyron <[email protected]>
2025-12-30 05:26 ` Re: psql: print values and return the COUNT(*) value to bash? hubert depesz lubaczewski <[email protected]>
0 siblings, 1 reply; 2+ messages in thread
From: Vincent Veyron @ 2025-12-29 16:40 UTC (permalink / raw)
To: [email protected]; +Cc: Ron Johnson <[email protected]>; pgsql-general
On Mon, 29 Dec 2025 11:11:58 +0100
hubert depesz lubaczewski <[email protected]> wrote:
Hi Ron, Hubert,
>
> Example:
>
> =$ cat z.sh
> #!/usr/bin/env bash
>
> table=pg_stat_all_tables
> field=last_autovacuum
>
> returned="$( psql -d depesz_explain -v "t=$table" -v "f=$field" -X << _SQL_
> select current_timestamp - min(:"f") as days_ago
> , min(:"f") as oldest_date
> , count(*) as cnt
> from :"t"
> _SQL_
> )"
> row_count="$( tail -n1 <<< "${returned}" | tr -cd 0-9 )"
> echo "Rowcount = $row_count"
> echo "Full output:"
> echo "${returned}"
>
> # vim: set filetype=bash shiftwidth=4 expandtab smarttab softtabstop=4 tabstop=4 textwidth=132 :
>
> =$ bash z.sh
> Rowcount = 1
> Full output:
> days_ago | oldest_date | cnt
> ------------------------+-------------------------------+-----
> 7 days 03:48:07.348247 | 2025-12-22 07:22:32.593814+01 | 212
> (1 row)
>
IIUC, Ron wants the 212 number?
Maybe use the -t switch, and 'cut' :
#!/usr/bin/env bash
table=pg_stat_all_tables
field=last_autovacuum
returned="$( psql -t -d vv -v "t=$table" -v "f=$field" -X << _SQL_
select current_timestamp - min(:"f") as days_ago
, min(:"f") as oldest_date
, count(*) as cnt
from :"t"
_SQL_
)"
row_count="$( tail -n1 <<< "${returned}" | cut -d "|" -f 3)"
echo "Rowcount = $row_count"
echo "Full output:"
echo "${returned}"
--
Bien à vous, Vincent Veyron
https://compta.libremen.com
Logiciel libre de comptabilité générale et analytique en partie double
^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: psql: print values and return the COUNT(*) value to bash?
2025-12-29 16:40 Re: psql: print values and return the COUNT(*) value to bash? Vincent Veyron <[email protected]>
@ 2025-12-30 05:26 ` hubert depesz lubaczewski <[email protected]>
0 siblings, 0 replies; 2+ messages in thread
From: hubert depesz lubaczewski @ 2025-12-30 05:26 UTC (permalink / raw)
To: Vincent Veyron <[email protected]>; +Cc: Ron Johnson <[email protected]>; pgsql-general
On Mon, Dec 29, 2025 at 05:40:23PM +0100, Vincent Veyron wrote:
> > =$ bash z.sh
> > Rowcount = 1
> > Full output:
> > days_ago | oldest_date | cnt
> > ------------------------+-------------------------------+-----
> > 7 days 03:48:07.348247 | 2025-12-22 07:22:32.593814+01 | 212
> > (1 row)
> >
>
> IIUC, Ron wants the 212 number?
>
> Maybe use the -t switch, and 'cut' :
Ah, that part I misunderstood.
Well, if there is only 1 row returned, always, then the simplest thing
would be to change
> row_count="$( tail -n1 <<< "${returned}" | cut -d "|" -f 3)"
to this:
row_count="$( awk 'NR==3 {print $NF}' <<< "${returned}" )"
format can stay the same, we don't need to psql -t, or -a, and it will
just work :)
Best regards,
depesz
^ permalink raw reply [nested|flat] 2+ messages in thread
end of thread, other threads:[~2025-12-30 05:26 UTC | newest]
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2025-12-29 16:40 Re: psql: print values and return the COUNT(*) value to bash? Vincent Veyron <[email protected]>
2025-12-30 05:26 ` hubert depesz lubaczewski <[email protected]>
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