Fix to_char for 1 BC. Previously it returned 1 AD.

Fix to_char(year) for BC dates.  Previously it returned one less than
the current year.

Add documentation mentioning that there is no 0 AD.

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index ccd430a97ff38aa8801360fb379c6a6f3b924257..19d357651786157e5b26e1f2f4c057704df0a7ba 100644 (file)
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -1,5 +1,5 @@
 
 
@@ -5216,8 +5216,7 @@ SELECT EXTRACT(SECOND FROM TIME '17:12:28.5');
       week
       
        
-        The number of
-        the week of the year that the day is in.  By definition
+        The number of the week of the year that the day is in.  By definition
         (ISO 8601), the first week of a year
         contains January 4 of that year.  (The ISO-8601
         week starts on Monday.)  In other words, the first Thursday of
@@ -5235,7 +5234,8 @@ SELECT EXTRACT(WEEK FROM TIMESTAMP '2001-02-16 20:38:40');
       year
       
        
-        The year field
+        The year field.  Keep in mind there is no 0 AD, so subtracting 
+        BC years from AD years should be done with care.
        
 
 

diff --git a/src/backend/utils/adt/datetime.c b/src/backend/utils/adt/datetime.c
index 5f340dd2a13838572843836254f142b9e1caabe0..be764ce45e287368734ca90e5119415eb86ea37c 100644 (file)
--- a/src/backend/utils/adt/datetime.c
+++ b/src/backend/utils/adt/datetime.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/utils/adt/datetime.c,v 1.125 2004/02/25 19:41:23 momjian Exp $
+ *   $PostgreSQL: pgsql/src/backend/utils/adt/datetime.c,v 1.126 2004/03/30 15:53:18 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -93,7 +93,7 @@ static datetkn datetktbl[] = {
    {"acsst", DTZ, POS(42)},    /* Cent. Australia */
    {"acst", DTZ, NEG(16)},     /* Atlantic/Porto Acre Summer Time */
    {"act", TZ, NEG(20)},       /* Atlantic/Porto Acre Time */
-   {DA_D, ADBC, AD},           /* "ad" for years >= 0 */
+   {DA_D, ADBC, AD},           /* "ad" for years > 0 */
    {"adt", DTZ, NEG(12)},      /* Atlantic Daylight Time */
    {"aesst", DTZ, POS(44)},    /* E. Australia */
    {"aest", TZ, POS(40)},      /* Australia Eastern Std Time */
@@ -139,7 +139,7 @@ static datetkn datetktbl[] = {
    {"azot", TZ, NEG(4)},       /* Azores Time */
    {"azst", DTZ, POS(20)},     /* Azerbaijan Summer Time */
    {"azt", TZ, POS(16)},       /* Azerbaijan Time */
-   {DB_C, ADBC, BC},           /* "bc" for years < 0 */
+   {DB_C, ADBC, BC},           /* "bc" for years <= 0 */
    {"bdst", TZ, POS(8)},       /* British Double Summer Time */
    {"bdt", TZ, POS(24)},       /* Dacca */
    {"bnt", TZ, POS(32)},       /* Brunei Darussalam Time */

diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index 25db1b0f5d3fb5dd55e0d4b5f3dc515fc5602ff5..3393a0ac4ce9682b945e15e2dfdde14b16c0f641 100644 (file)
--- 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 1.72 2004/01/07 18:56:28 neilc Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/formatting.c,v 1.73 2004/03/30 15:53:18 momjian Exp $
  *
  *
  *  Portions Copyright (c) 1999-2003, PostgreSQL Global Development Group
@@ -169,7 +169,7 @@ static char *months_full[] = {
  * AC / DC
  * ----------
  */
-#define YEAR_ABS(_y)   (_y < 0 ? -(_y -1) : _y)
+#define YEAR_ABS(_y)   (_y <= 0 ? -(_y -1) : _y)
 #define BC_STR_ORIG " BC"
 
 #define A_D_STR        "A.D."
@@ -2119,7 +2119,7 @@ dch_date(int arg, char *inout, int suf, int flag, FormatNode *node, void *data)
        case DCH_B_C:
            if (flag == TO_CHAR)
            {
-               strcpy(inout, (tm->tm_year < 0 ? B_C_STR : A_D_STR));
+               strcpy(inout, (tm->tm_year <= 0 ? B_C_STR : A_D_STR));
                return 3;
 
            }
@@ -2134,7 +2134,7 @@ dch_date(int arg, char *inout, int suf, int flag, FormatNode *node, void *data)
        case DCH_BC:
            if (flag == TO_CHAR)
            {
-               strcpy(inout, (tm->tm_year < 0 ? BC_STR : AD_STR));
+               strcpy(inout, (tm->tm_year <= 0 ? BC_STR : AD_STR));
                return 1;
 
            }
@@ -2149,7 +2149,7 @@ dch_date(int arg, char *inout, int suf, int flag, FormatNode *node, void *data)
        case DCH_b_c:
            if (flag == TO_CHAR)
            {
-               strcpy(inout, (tm->tm_year < 0 ? b_c_STR : a_d_STR));
+               strcpy(inout, (tm->tm_year <= 0 ? b_c_STR : a_d_STR));
                return 3;
 
            }
@@ -2164,7 +2164,7 @@ dch_date(int arg, char *inout, int suf, int flag, FormatNode *node, void *data)
        case DCH_bc:
            if (flag == TO_CHAR)
            {
-               strcpy(inout, (tm->tm_year < 0 ? bc_STR : ad_STR));
+               strcpy(inout, (tm->tm_year <= 0 ? bc_STR : ad_STR));
                return 1;
 
            }

diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c
index 11a75cc2bd56885b1f9a9e8c52e989b6c629bdc7..dafc8ae5bedace622f141063ac7d7a4b17b28f8f 100644 (file)
--- a/src/backend/utils/adt/timestamp.c
+++ b/src/backend/utils/adt/timestamp.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.102 2004/03/22 01:38:17 tgl Exp $
+ *   $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.103 2004/03/30 15:53:18 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -3261,7 +3261,11 @@ timestamp_part(PG_FUNCTION_ARGS)
                break;
 
            case DTK_YEAR:
-               result = tm->tm_year;
+               if (tm->tm_year > 0)
+                   result = tm->tm_year;
+               else
+                   /* there is no year 0, just 1 BC and 1 AD*/
+                   result = tm->tm_year - 1;   
                break;
 
            case DTK_DECADE: