Le mar. 2 févr. 2021 à 02:14, Matt Zagrabelny <mzagr...@d.umn.edu> a écrit :
> > > On Mon, Feb 1, 2021 at 6:35 PM Tom Lane <t...@sss.pgh.pa.us> wrote: > >> Matt Zagrabelny <mzagr...@d.umn.edu> writes: >> > On Mon, Feb 1, 2021 at 5:57 PM Rob Sargent <robjsarg...@gmail.com> >> wrote: >> >> You got one null from count(*) likely. >> >> > What is count(*) counting then? I thought it was rows. >> >> Yeah, but count(id) only counts rows where id isn't null. >> > > I guess I'm still not understanding it... > > I don't have any rows where id is null: > > $ select count(*) from call_records where id is null; > count > ═══════ > 0 > (1 row) > > Time: 0.834 ms > $ > > select count(id) from call_records where id is null; > count > ═══════ > 0 > (1 row) > > Time: 0.673 ms > > Which field is count(*) counting if it is counting nulls? > You're doing a left join, so I guess there's no row where call_records.timestamp::date = 2020-08-30. That would result with a NULL id. Guillaume
