On 3 February 2011 13:58, Thom Brown <t...@linux.com> wrote: > On 3 February 2011 13:32, Thom Brown <t...@linux.com> wrote: >> Actually, further testing indicates this causes other problems: >> >> postgres=# SELECT x FROM generate_series(1, 9,-1) AS a(x); >> x >> --- >> 1 >> (1 row) >> >> Should return no rows. >> >> postgres=# SELECT x FROM generate_series(1, 9,3) AS a(x); >> x >> ---- >> 1 >> 4 >> 7 >> 10 >> (4 rows) >> >> Should return 3 rows. > > Still messy code, but the attached patch does the job now: > > postgres=# SELECT x FROM > generate_series(2147483643::int4,2147483647::int4) AS a(x); > x > ------------ > 2147483643 > 2147483644 > 2147483645 > 2147483646 > 2147483647 > (5 rows) > > postgres=# SELECT x FROM > generate_series(2147483642::int4,2147483647::int4, 2) AS a(x); > x > ------------ > 2147483642 > 2147483644 > 2147483646 > (3 rows) > > postgres=# SELECT x FROM > generate_series(2147483643::int4,2147483647::int4, 6) AS a(x); > x > ------------ > 2147483643 > (1 row) > > postgres=# SELECT x FROM generate_series((-2147483643)::int4, > (-2147483648)::int4, -1) AS a(x); > x > ------------- > -2147483643 > -2147483644 > -2147483645 > -2147483646 > -2147483647 > -2147483648 > (6 rows) > > postgres=# SELECT x FROM generate_series(1, 9,-1) AS a(x); > x > --- > (0 rows) > > postgres=# SELECT x FROM generate_series(1, 9,3) AS a(x); > x > --- > 1 > 4 > 7 > (3 rows) >
Copying to -hackers. The issue is that generate_series will not return if the series hits either the upper or lower boundary during increment, or goes beyond it. The attached patch fixes this behaviour, but should probably be done a better way. The first 3 examples above will not return. -- Thom Brown Twitter: @darkixion IRC (freenode): dark_ixion Registered Linux user: #516935
generate_series_fix.v3.patch
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