Fix handling of CC (century) format spec in to_date/to_char. According to

standard convention the 21st century runs from 2001-2100, not 2000-2099,
so make it work like that.  Per bug #2885 from Akio Iwaasa.

Backpatch to 8.2, but no further, since this is really a definitional
change; users of older branches are probably more interested in stability.

4 files changed, 51 insertions, 48 deletions

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1e092c4ce7..5f7a8322f7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.347 2006/11/25 00:38:53 momjian Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.347.2.1 2007/01/12 23:35:03 tgl Exp $ -->
 
  <chapter id="functions">
   <title>Functions and Operators</title>
@@ -4617,7 +4617,7 @@ SELECT SUBSTRING('XY1234Z', 'Y*?([0-9]{1,3})');
        </row>
        <row>
         <entry><literal>CC</literal></entry>
-        <entry>century (2 digits)</entry>
+        <entry>century (2 digits) (The twenty-first century starts on 2001-01-01.)</entry>
        </row>
        <row>
         <entry><literal>J</literal></entry>
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index 2e1a5ac3eb..cb6a109bf4 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -1,7 +1,7 @@
 /* -----------------------------------------------------------------------
  * formatting.c
  *
- * $PostgreSQL: pgsql/src/backend/utils/adt/formatting.c,v 1.116 2006/11/28 12:53:44 petere Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/formatting.c,v 1.116.2.1 2007/01/12 23:35:03 tgl Exp $
  *
  *
  *	 Portions Copyright (c) 1999-2006, PostgreSQL Global Development Group
@@ -2445,7 +2445,10 @@ dch_date(int arg, char *inout, int suf, bool is_to_char, bool is_interval,
 		case DCH_CC:
 			if (is_to_char)
 			{
-				i = tm->tm_year / 100 + ((is_interval) ? 0 : 1);
+				if (is_interval)			/* straight calculation */
+					i = tm->tm_year / 100;
+				else						/* century 21 starts in 2001 */
+					i = (tm->tm_year - 1) / 100 + 1;
 				if (i <= 99 && i >= -99)
 					sprintf(inout, "%0*d", S_FM(suf) ? 0 : 2, i);
 				else
@@ -3295,9 +3298,6 @@ do_to_timestamp(text *date_txt, text *fmt,
 		tm->tm_sec = x;
 	}
 
-	if (tmfc.cc)
-		tm->tm_year = (tmfc.cc - 1) * 100;
-
 	if (tmfc.ww)
 		tmfc.ddd = (tmfc.ww - 1) * 7 + 1;
 
@@ -3347,24 +3347,27 @@ do_to_timestamp(text *date_txt, text *fmt,
 
 	if (tmfc.year)
 	{
-		if (tmfc.yysz == 2 && tmfc.cc)
-		{
-			/*
-			 * CC and YY defined why -[2000|1900]? See dch_date() DCH_YY code.
-			 */
-			tm->tm_year = (tmfc.cc - 1) * 100 + (tmfc.year >= 2000 ? tmfc.year - 2000 : tmfc.year - 1900);
-		}
-		else if (tmfc.yysz == 1 && tmfc.cc)
+		/*
+		 * If CC and YY (or Y) are provided, use YY as 2 low-order digits
+		 * for the year in the given century.  Keep in mind that the 21st
+		 * century runs from 2001-2100, not 2000-2099.
+		 *
+		 * If a 4-digit year is provided, we use that and ignore CC.
+		 */
+		if (tmfc.cc && tmfc.yysz <= 2)
 		{
-			/*
-			 * CC and Y defined
-			 */
-			tm->tm_year = (tmfc.cc - 1) * 100 + tmfc.year - 2000;
+			tm->tm_year = tmfc.year % 100;
+			if (tm->tm_year)
+				tm->tm_year += (tmfc.cc - 1) * 100;
+			else
+				tm->tm_year = tmfc.cc * 100;
 		}
 		else
-			/* set year (and ignore CC if defined) */
 			tm->tm_year = tmfc.year;
 	}
+	else if (tmfc.cc)			/* use first year of century */
+		tm->tm_year = (tmfc.cc - 1) * 100 + 1;
+
 	if (tmfc.bc)
 	{
 		if (tm->tm_year > 0)
diff --git a/src/test/regress/expected/timestamp.out b/src/test/regress/expected/timestamp.out
index c145279e73..c26cb9ec99 100644
--- a/src/test/regress/expected/timestamp.out
+++ b/src/test/regress/expected/timestamp.out
@@ -867,11 +867,11 @@ SELECT '' AS to_char_3, to_char(d1, 'Y,YYY YYYY YYY YY Y CC Q MM WW DDD DD D J')
            | 1,997 1997 997 97 7 20 1 02 06 041 10 2 2450490
            | 1,997 1997 997 97 7 20 2 06 23 161 10 3 2450610
            | 2,001 2001 001 01 1 21 3 09 38 265 22 7 2452175
-           | 2,000 2000 000 00 0 21 1 03 11 075 15 4 2451619
-           | 2,000 2000 000 00 0 21 1 03 11 075 15 4 2451619
-           | 2,000 2000 000 00 0 21 1 03 11 075 15 4 2451619
-           | 2,000 2000 000 00 0 21 1 03 11 075 15 4 2451619
-           | 2,000 2000 000 00 0 21 1 03 11 075 15 4 2451619
+           | 2,000 2000 000 00 0 20 1 03 11 075 15 4 2451619
+           | 2,000 2000 000 00 0 20 1 03 11 075 15 4 2451619
+           | 2,000 2000 000 00 0 20 1 03 11 075 15 4 2451619
+           | 2,000 2000 000 00 0 20 1 03 11 075 15 4 2451619
+           | 2,000 2000 000 00 0 20 1 03 11 075 15 4 2451619
            | 1,997 1997 997 97 7 20 1 02 06 041 10 2 2450490
            | 1,997 1997 997 97 7 20 1 02 06 041 10 2 2450490
            | 1,997 1997 997 97 7 20 1 02 06 041 10 2 2450490
@@ -912,8 +912,8 @@ SELECT '' AS to_char_3, to_char(d1, 'Y,YYY YYYY YYY YY Y CC Q MM WW DDD DD D J')
            | 1,997 1997 997 97 7 20 4 12 52 364 30 3 2450813
            | 1,997 1997 997 97 7 20 4 12 53 365 31 4 2450814
            | 1,999 1999 999 99 9 20 4 12 53 365 31 6 2451544
-           | 2,000 2000 000 00 0 21 1 01 01 001 01 7 2451545
-           | 2,000 2000 000 00 0 21 4 12 53 366 31 1 2451910
+           | 2,000 2000 000 00 0 20 1 01 01 001 01 7 2451545
+           | 2,000 2000 000 00 0 20 4 12 53 366 31 1 2451910
            | 2,001 2001 001 01 1 21 1 01 01 001 01 2 2451911
 (65 rows)
 
@@ -938,11 +938,11 @@ SELECT '' AS to_char_4, to_char(d1, 'FMY,YYY FMYYYY FMYYY FMYY FMY FMCC FMQ FMMM
            | 1,997 1997 997 97 7 20 1 2 6 41 10 2 2450490
            | 1,997 1997 997 97 7 20 2 6 23 161 10 3 2450610
            | 2,001 2001 001 01 1 21 3 9 38 265 22 7 2452175
-           | 2,000 2000 000 00 0 21 1 3 11 75 15 4 2451619
-           | 2,000 2000 000 00 0 21 1 3 11 75 15 4 2451619
-           | 2,000 2000 000 00 0 21 1 3 11 75 15 4 2451619
-           | 2,000 2000 000 00 0 21 1 3 11 75 15 4 2451619
-           | 2,000 2000 000 00 0 21 1 3 11 75 15 4 2451619
+           | 2,000 2000 000 00 0 20 1 3 11 75 15 4 2451619
+           | 2,000 2000 000 00 0 20 1 3 11 75 15 4 2451619
+           | 2,000 2000 000 00 0 20 1 3 11 75 15 4 2451619
+           | 2,000 2000 000 00 0 20 1 3 11 75 15 4 2451619
+           | 2,000 2000 000 00 0 20 1 3 11 75 15 4 2451619
            | 1,997 1997 997 97 7 20 1 2 6 41 10 2 2450490
            | 1,997 1997 997 97 7 20 1 2 6 41 10 2 2450490
            | 1,997 1997 997 97 7 20 1 2 6 41 10 2 2450490
@@ -983,8 +983,8 @@ SELECT '' AS to_char_4, to_char(d1, 'FMY,YYY FMYYYY FMYYY FMYY FMY FMCC FMQ FMMM
            | 1,997 1997 997 97 7 20 4 12 52 364 30 3 2450813
            | 1,997 1997 997 97 7 20 4 12 53 365 31 4 2450814
            | 1,999 1999 999 99 9 20 4 12 53 365 31 6 2451544
-           | 2,000 2000 000 00 0 21 1 1 1 1 1 7 2451545
-           | 2,000 2000 000 00 0 21 4 12 53 366 31 1 2451910
+           | 2,000 2000 000 00 0 20 1 1 1 1 1 7 2451545
+           | 2,000 2000 000 00 0 20 4 12 53 366 31 1 2451910
            | 2,001 2001 001 01 1 21 1 1 1 1 1 2 2451911
 (65 rows)
 
diff --git a/src/test/regress/expected/timestamptz.out b/src/test/regress/expected/timestamptz.out
index 4a17503324..be3d7bed5d 100644
--- a/src/test/regress/expected/timestamptz.out
+++ b/src/test/regress/expected/timestamptz.out
@@ -887,11 +887,11 @@ SELECT '' AS to_char_3, to_char(d1, 'Y,YYY YYYY YYY YY Y CC Q MM WW DDD DD D J')
            | 1,997 1997 997 97 7 20 1 02 06 041 10 2 2450490
            | 1,997 1997 997 97 7 20 2 06 23 161 10 3 2450610
            | 2,001 2001 001 01 1 21 3 09 38 265 22 7 2452175
-           | 2,000 2000 000 00 0 21 1 03 11 075 15 4 2451619
-           | 2,000 2000 000 00 0 21 1 03 11 075 15 4 2451619
-           | 2,000 2000 000 00 0 21 1 03 11 075 15 4 2451619
-           | 2,000 2000 000 00 0 21 1 03 11 075 15 4 2451619
-           | 2,000 2000 000 00 0 21 1 03 11 075 15 4 2451619
+           | 2,000 2000 000 00 0 20 1 03 11 075 15 4 2451619
+           | 2,000 2000 000 00 0 20 1 03 11 075 15 4 2451619
+           | 2,000 2000 000 00 0 20 1 03 11 075 15 4 2451619
+           | 2,000 2000 000 00 0 20 1 03 11 075 15 4 2451619
+           | 2,000 2000 000 00 0 20 1 03 11 075 15 4 2451619
            | 1,997 1997 997 97 7 20 1 02 06 041 10 2 2450490
            | 1,997 1997 997 97 7 20 1 02 06 041 10 2 2450490
            | 1,997 1997 997 97 7 20 1 02 06 041 10 2 2450490
@@ -933,8 +933,8 @@ SELECT '' AS to_char_3, to_char(d1, 'Y,YYY YYYY YYY YY Y CC Q MM WW DDD DD D J')
            | 1,997 1997 997 97 7 20 4 12 52 364 30 3 2450813
            | 1,997 1997 997 97 7 20 4 12 53 365 31 4 2450814
            | 1,999 1999 999 99 9 20 4 12 53 365 31 6 2451544
-           | 2,000 2000 000 00 0 21 1 01 01 001 01 7 2451545
-           | 2,000 2000 000 00 0 21 4 12 53 366 31 1 2451910
+           | 2,000 2000 000 00 0 20 1 01 01 001 01 7 2451545
+           | 2,000 2000 000 00 0 20 4 12 53 366 31 1 2451910
            | 2,001 2001 001 01 1 21 1 01 01 001 01 2 2451911
 (66 rows)
 
@@ -960,11 +960,11 @@ SELECT '' AS to_char_4, to_char(d1, 'FMY,YYY FMYYYY FMYYY FMYY FMY FMCC FMQ FMMM
            | 1,997 1997 997 97 7 20 1 2 6 41 10 2 2450490
            | 1,997 1997 997 97 7 20 2 6 23 161 10 3 2450610
            | 2,001 2001 001 01 1 21 3 9 38 265 22 7 2452175
-           | 2,000 2000 000 00 0 21 1 3 11 75 15 4 2451619
-           | 2,000 2000 000 00 0 21 1 3 11 75 15 4 2451619
-           | 2,000 2000 000 00 0 21 1 3 11 75 15 4 2451619
-           | 2,000 2000 000 00 0 21 1 3 11 75 15 4 2451619
-           | 2,000 2000 000 00 0 21 1 3 11 75 15 4 2451619
+           | 2,000 2000 000 00 0 20 1 3 11 75 15 4 2451619
+           | 2,000 2000 000 00 0 20 1 3 11 75 15 4 2451619
+           | 2,000 2000 000 00 0 20 1 3 11 75 15 4 2451619
+           | 2,000 2000 000 00 0 20 1 3 11 75 15 4 2451619
+           | 2,000 2000 000 00 0 20 1 3 11 75 15 4 2451619
            | 1,997 1997 997 97 7 20 1 2 6 41 10 2 2450490
            | 1,997 1997 997 97 7 20 1 2 6 41 10 2 2450490
            | 1,997 1997 997 97 7 20 1 2 6 41 10 2 2450490
@@ -1006,8 +1006,8 @@ SELECT '' AS to_char_4, to_char(d1, 'FMY,YYY FMYYYY FMYYY FMYY FMY FMCC FMQ FMMM
            | 1,997 1997 997 97 7 20 4 12 52 364 30 3 2450813
            | 1,997 1997 997 97 7 20 4 12 53 365 31 4 2450814
            | 1,999 1999 999 99 9 20 4 12 53 365 31 6 2451544
-           | 2,000 2000 000 00 0 21 1 1 1 1 1 7 2451545
-           | 2,000 2000 000 00 0 21 4 12 53 366 31 1 2451910
+           | 2,000 2000 000 00 0 20 1 1 1 1 1 7 2451545
+           | 2,000 2000 000 00 0 20 4 12 53 366 31 1 2451910
            | 2,001 2001 001 01 1 21 1 1 1 1 1 2 2451911
 (66 rows)