diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 521fa9e0cbe..96edf78983a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -6175,8 +6175,18 @@ SELECT regexp_matches('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
- The YYYY conversion from string to timestamp or
- date has a restriction when processing years with more than 4 digits. You must
+ In to_timestamp and to_date,
+ negative years are treated as signifying BC. If you write both a
+ negative year and an explicit BC field, you get AD
+ again. An input of year zero is treated as 1 BC.
+
+
+
+
+
+ In to_timestamp and to_date,
+ the YYYY conversion has a restriction when
+ processing years with more than 4 digits. You must
use some non-digit character or template after YYYY,
otherwise the year is always interpreted as 4 digits. For example
(with the year 20000):
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index 24484b4c57f..d4c773e422f 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -3693,8 +3693,11 @@ do_to_timestamp(text *date_txt, text *fmt,
/* If a 4-digit year is provided, we use that and ignore CC. */
{
tm->tm_year = tmfc.year;
- if (tmfc.bc && tm->tm_year > 0)
- tm->tm_year = -(tm->tm_year - 1);
+ if (tmfc.bc)
+ tm->tm_year = -tm->tm_year;
+ /* correct for our representation of BC years */
+ if (tm->tm_year < 0)
+ tm->tm_year++;
}
}
else if (tmfc.cc) /* use first year of century */
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index 28ef3d2f405..699e254a21d 100644
--- a/src/test/regress/expected/horology.out
+++ b/src/test/regress/expected/horology.out
@@ -2957,6 +2957,45 @@ SELECT to_date('2458872', 'J');
01-23-2020
(1 row)
+--
+-- Check handling of BC dates
+--
+SELECT to_date('44-02-01 BC','YYYY-MM-DD BC');
+ to_date
+---------------
+ 02-01-0044 BC
+(1 row)
+
+SELECT to_date('-44-02-01','YYYY-MM-DD');
+ to_date
+---------------
+ 02-01-0044 BC
+(1 row)
+
+SELECT to_date('-44-02-01 BC','YYYY-MM-DD BC');
+ to_date
+------------
+ 02-01-0044
+(1 row)
+
+SELECT to_timestamp('44-02-01 11:12:13 BC','YYYY-MM-DD HH24:MI:SS BC');
+ to_timestamp
+---------------------------------
+ Fri Feb 01 11:12:13 0044 PST BC
+(1 row)
+
+SELECT to_timestamp('-44-02-01 11:12:13','YYYY-MM-DD HH24:MI:SS');
+ to_timestamp
+---------------------------------
+ Fri Feb 01 11:12:13 0044 PST BC
+(1 row)
+
+SELECT to_timestamp('-44-02-01 11:12:13 BC','YYYY-MM-DD HH24:MI:SS BC');
+ to_timestamp
+------------------------------
+ Mon Feb 01 11:12:13 0044 PST
+(1 row)
+
--
-- Check handling of multiple spaces in format and/or input
--
diff --git a/src/test/regress/sql/horology.sql b/src/test/regress/sql/horology.sql
index a1cd2eea174..b0402ae4fe2 100644
--- a/src/test/regress/sql/horology.sql
+++ b/src/test/regress/sql/horology.sql
@@ -455,6 +455,17 @@ SELECT to_date('1 4 1902', 'Q MM YYYY'); -- Q is ignored
SELECT to_date('3 4 21 01', 'W MM CC YY');
SELECT to_date('2458872', 'J');
+--
+-- Check handling of BC dates
+--
+
+SELECT to_date('44-02-01 BC','YYYY-MM-DD BC');
+SELECT to_date('-44-02-01','YYYY-MM-DD');
+SELECT to_date('-44-02-01 BC','YYYY-MM-DD BC');
+SELECT to_timestamp('44-02-01 11:12:13 BC','YYYY-MM-DD HH24:MI:SS BC');
+SELECT to_timestamp('-44-02-01 11:12:13','YYYY-MM-DD HH24:MI:SS');
+SELECT to_timestamp('-44-02-01 11:12:13 BC','YYYY-MM-DD HH24:MI:SS BC');
+
--
-- Check handling of multiple spaces in format and/or input
--