From 07c4b6ac7d6e467f9db681772b5d5101144fcfe7 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Thu, 12 Dec 2019 12:30:44 -0500 Subject: [PATCH] Fix EXTRACT(ISOYEAR FROM timestamp) for years BC. The test cases added by commit 26ae3aa80 exposed an old oversight in timestamp[tz]_part: they didn't correct the result of date2isoyear() for BC years, so that we produced an off-by-one answer for such years. Fix that, and back-patch to all supported branches. Discussion: https://postgr.es/m/SG2PR06MB37762CAE45DB0F6CA7001EA9B6550@SG2PR06MB3776.apcprd06.prod.outlook.com --- src/backend/utils/adt/timestamp.c | 7 +++++++ src/test/regress/expected/timestamp.out | 2 +- src/test/regress/expected/timestamptz.out | 2 +- 3 files changed, 9 insertions(+), 2 deletions(-) diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c index 9151d347ed..666452d81e 100644 --- a/src/backend/utils/adt/timestamp.c +++ b/src/backend/utils/adt/timestamp.c @@ -4359,6 +4359,7 @@ date2isoweek(int year, int mon, int mday) /* date2isoyear() * * Returns ISO 8601 year number. + * Note: zero or negative results follow the year-zero-exists convention. */ int date2isoyear(int year, int mon, int mday) @@ -4633,6 +4634,9 @@ timestamp_part(PG_FUNCTION_ARGS) case DTK_ISOYEAR: result = date2isoyear(tm->tm_year, tm->tm_mon, tm->tm_mday); + /* Adjust BC years */ + if (result <= 0) + result -= 1; break; case DTK_DOW: @@ -4829,6 +4833,9 @@ timestamptz_part(PG_FUNCTION_ARGS) case DTK_ISOYEAR: result = date2isoyear(tm->tm_year, tm->tm_mon, tm->tm_mday); + /* Adjust BC years */ + if (result <= 0) + result -= 1; break; case DTK_DOW: diff --git a/src/test/regress/expected/timestamp.out b/src/test/regress/expected/timestamp.out index 543e3a2017..f1100488b7 100644 --- a/src/test/regress/expected/timestamp.out +++ b/src/test/regress/expected/timestamp.out @@ -809,7 +809,7 @@ SELECT d1 as "timestamp", Fri Feb 14 17:32:01 1997 | 1997 | 7 | 5 | 5 | 45 Sat Feb 15 17:32:01 1997 | 1997 | 7 | 6 | 6 | 46 Sun Feb 16 17:32:01 1997 | 1997 | 7 | 7 | 0 | 47 - Tue Feb 16 17:32:01 0097 BC | -96 | 7 | 2 | 2 | 47 + Tue Feb 16 17:32:01 0097 BC | -97 | 7 | 2 | 2 | 47 Sat Feb 16 17:32:01 0097 | 97 | 7 | 6 | 6 | 47 Thu Feb 16 17:32:01 0597 | 597 | 7 | 4 | 4 | 47 Tue Feb 16 17:32:01 1097 | 1097 | 7 | 2 | 2 | 47 diff --git a/src/test/regress/expected/timestamptz.out b/src/test/regress/expected/timestamptz.out index 8f0a0f5b41..09ff200243 100644 --- a/src/test/regress/expected/timestamptz.out +++ b/src/test/regress/expected/timestamptz.out @@ -918,7 +918,7 @@ SELECT d1 as timestamptz, Fri Feb 14 17:32:01 1997 PST | 1997 | 7 | 5 | 5 | 45 Sat Feb 15 17:32:01 1997 PST | 1997 | 7 | 6 | 6 | 46 Sun Feb 16 17:32:01 1997 PST | 1997 | 7 | 7 | 0 | 47 - Tue Feb 16 17:32:01 0097 PST BC | -96 | 7 | 2 | 2 | 47 + Tue Feb 16 17:32:01 0097 PST BC | -97 | 7 | 2 | 2 | 47 Sat Feb 16 17:32:01 0097 PST | 97 | 7 | 6 | 6 | 47 Thu Feb 16 17:32:01 0597 PST | 597 | 7 | 4 | 4 | 47 Tue Feb 16 17:32:01 1097 PST | 1097 | 7 | 2 | 2 | 47