sorry, my bad, thanks for the clarification! вт, 21 січ. 2025 р., 18:40 користувач David G. Johnston < david.g.johns...@gmail.com> пише:
> On Tue, Jan 21, 2025 at 10:39 AM Tom Lane <t...@sss.pgh.pa.us> wrote: > >> PG Doc comments form <nore...@postgresql.org> writes: >> > EXPECTED: >> > As shown here, the rank function produces a numerical rank for each >> distinct >> > PARTITION BY value in the current row's partition, using the order >> defined >> > by the ORDER BY clause. rank needs no explicit parameter, because its >> > behavior is entirely determined by the OVER clause. >> >> > ACTUAL: >> > As shown here, the rank function produces a numerical rank for each >> distinct >> > ORDER BY value in the current row's partition, using the order defined >> by >> > the ORDER BY clause. rank needs no explicit parameter, because its >> behavior >> > is entirely determined by the OVER clause. >> >> Hmm, I think the current text is correct, or at least more nearly >> correct than what you suggest. > > > > > >> Look at the example: >> >> <programlisting> >> SELECT depname, empno, salary, >> rank() OVER (PARTITION BY depname ORDER BY salary DESC) >> FROM empsalary; >> </programlisting> >> >> <screen> >> depname | empno | salary | rank >> -----------+-------+--------+------ >> develop | 8 | 6000 | 1 >> develop | 10 | 5200 | 2 >> develop | 11 | 5200 | 2 >> develop | 9 | 4500 | 4 >> develop | 7 | 4200 | 5 >> personnel | 2 | 3900 | 1 >> personnel | 5 | 3500 | 2 >> sales | 1 | 5000 | 1 >> sales | 4 | 4800 | 2 >> sales | 3 | 4800 | 2 >> (10 rows) >> </screen> >> >> The ranks are separate within each partition (depname), and >> within a partition rows having the same salary get the >> same rank. >> >> regards, tom lane >> >> >>
