MDEV-19683 Add support for Oracle TO_DATE()

Syntax:
TO_DATE(string_expression [DEFAULT string_expression ON CONVERSION ERROR],
        format_string [,NLS_FORMAT_STRING])
The format_string has the same format elements as TO_CHAR(), except a
few elements that are not supported/usable for TO_DATE().
TO_DATE() returns a datetime or date value, depending on if the format
element FF is used.

Allowed separators, same as TO_CHAR():
space, tab and any of !#%'()*+,-./:;<=>

'&' can also be used if next character is not a character a-z or A-Z
"text' indicates a text string that is verbatim in the format. One cannot
use " as a separator.

Format elements supported by TO_DATE():
AD          Anno Domini ("in the year of the Lord")
AD_DOT      Anno Domini ("in the year of the Lord")
AM          Meridian indicator (Before midday)
AM_DOT      Meridian indicator (Before midday)
DAY         Name of day
DD          Day (1-31)
DDD         Day of year (1-336)
DY          Abbreviated name of day
FF[1-6]     Fractional seconds
HH          Hour (1-12)
HH12        Hour (1-12)
HH24        Hour (0-23)
MI          Minutes (0-59)
MM          Month (1-12)
MON         Abbreviated name of month
MONTH       Name of Month
PM          Meridian indicator (After midday)
PM_DOT      Meridian indicator (After midday)
RR          20th century dates in the 21st century. 2 digits
            50-99 is assumed from 2000, 0-49 is assumed from 1900.
RRRR        20th century dates in the 21st century. 4 digits
SS          Seconds
SYYYY       Signed 4 digit year; MariaDB only supports positive years
Y           1 digit year
YY          2 digits year
YYY         3 digits year
YYYY        4 digits year

Note that if there is a missing part of the date, the current date is used!
For example if 'MM-DD HH-MM-SS' then the current year will be used.
(Oracle behaviour)

Not supported options:
- BC, D, DL, DS, E, EE, FM, FX, RM, SSSSS, TS, TZD, TZH, TZR, X,SY
  BC is not supported by MariaDB datetime.
- Most of the other are exotic formats does not make sence in MariaDB as
   we return datetime or datetime with fractions, not string.
- D (day-of-week) is not supported as it is not clear exactly how it would
  map to MariaDB. This element depends on the NLS territory of the session.
- RR only works with 2 digit years (In Oracle RR can also work with 4
  digit years in some context but the rules are not clear).

Extensions / differences compared to Oracle;
- MariaDB supports FF (fractional seconds).  If FF[#] is used,
  then TO_DATE will return a datetime with # of subseconds.
  If FF is not used a datetime will be returned.
  There is warning (no error) if string contains more digts than what
  is specified with F(#]
- Names can be shortened to it's unique prefix. For example January and Ja
  works fine.
- No error if the date string is shorter format_string and the next
  not used character is not a number.. This is useful to get a date
  from a mixed set of strings in date or datetime format.
  Oracle gives an error if date string is too short.
- MariaDB supports short locales as language names
- NLS_DATE_FORMAT can use both " and ' for quoting.
- NLS_DATE_FORMAT must be a constant string.
  - This is to ensure that the server knows which locale to use
    when executing the function.

New formats handled by TO_CHAR():
FF[1-6]     Fractional seconds
DDD         Daynumber 1-366
IW          Week 1-53 according to ISO 8601
I           1 digit year according to ISO 8601
IY          2 digit year according to ISO 8601
IYY         3 digit year according to ISO 8601
IYYY        4 digit year according to ISO 8601
SYYY        4 digit year according to ISO 8601 (Oracle can do signed)

Supported NLS_FORMAT_STRING options are:
NLS_CALENDAR=GREGORIAN
NLS_DATE_LANGUAGE=language

Support languages are:
- All MariaDB short locales, like en_AU.
- The following Oracle language names:
ALBANIAN, AMERICAN, ARABIC, BASQUE, BELARUSIAN, BRAZILIAN PORTUGUESE
BULGARIAN, CANADIAN FRENCH, CATALAN, CROATIAN, CYRILLIC SERBIAN CZECH,
DANISH, DUTCH, ENGLISH, ESTONIAN, FINNISH, FRENCH, GERMAN,
GREEK, HEBREW, HINDI, HUNGARIAN, ICELANDIC, INDONESIAN ITALIAN,
JAPANESE, KANNADA, KOREAN, LATIN AMERICAN SPANISH, LATVIAN,
LITHUANIAN, MACEDONIAN, MALAY, MEXICAN SPANISH, NORWEGIAN, POLISH,
PORTUGUESE, ROMANIAN, RUSSIAN, SIMPLIFIED CHINESE, SLOVAK, SLOVENIAN,
SPANISH, SWAHILI, SWEDISH, TAMIL, THAI, TRADITIONAL CHINESE, TURKISH,
UKRAINIAN, VIETNAMESE

Development bugs fixed:
MDEV-38403 Server crashes in Item_func_to_date::fix_length_and_dec upon
           using an invalid argument
MDEV-38400 compat/oracle.func_to_date fails with PS protocol and cursor
           protocol (Fixed by Serg)
MDEV-38404 TO_DATE: MTR coverage omissions, round 1
MDEV-38509 TO_DATE: AD_DOT does not appear to be supported
MDEV-38513 TO_DATE: NULL value for format string causes assertion failure
MDEV-38521 TO_DATE: Date strings with non-ASCII symbols cause warnings
           and wrong results
MDEV-38578 TO_DATE: Possibly unexpected results upon wrong input
MDEV-38582 TO_DATE: NLS_DATE_LANGUAGE=JAPANESE does not parse values
           which work in Oracle
MDEV-38584 TO_DATE: NLS_DATE_LANGUAGE=VIETNAMESE does not parse values
           which work in Oracle
MDEV-38703 TO_DATE: Quotation for multi-word NLS_DATE_LANGUAGE leads
           to syntax error in view definition
MDEV-38675 TO_DATE: MSAN/Valgrind/UBSAN errors in
           extract_oracle_date_time
MDEV-38635 TO_DATE: UBSAN errors in item_timefunc.h upon comparison with
           a view column
MDEV-38719 TO_DATE: Assertion `&my_charset_bin != charset()' failed in
           String::append_for_single_quote_using_mb_wc

Known issues:
- Format string character matches inside quotes are done
  one-letter-to-one-letter, like in LIKE predicate. That means things
  like expansions and contractions do not work.
  For example 'ss' does not match 'ß' in collations which treat them
  as equal for the comparison operator.
  Match is done taking into account case and accent sensitivity
  of the subject argument collation, so for example this now works:
  MariaDB [test]> SELECT TO_DATE('1920á12','YYYY"a"MM') AS c;
  +---------------------+
  | c                   |
  +---------------------+
  | 1920-12-17 00:00:00 |
  +---------------------+

Co-author and reviewer: Alexander Barkov <[email protected]>

Author: montywi

include/typelib.h

@@ -34,7 +34,7 @@ typedef struct st_typelib {	/* Different types saved here */
   const int *hidden_values;
 } TYPELIB;
 
-#define CREATE_TYPELIB_FOR(X) { (unsigned int)(sizeof(X)/sizeof(X[0])) - 1, "", X, NULL, NULL }
+#define CREATE_TYPELIB_FOR(X) { (unsigned int)(sizeof(X)/sizeof(X[0])) - 1, "", X, (uint[(sizeof(X)/sizeof(X[0]))-1]){0}, NULL }
 
 extern my_ulonglong find_typeset(const char *x, TYPELIB *typelib,
                                  int *error_position);

mysql-test/suite/compat/oracle/r/func_to_char.result

@@ -154,6 +154,43 @@ A.D.9999-12-31	PM11:59:59	A.D..9999-12-31 P.M.23:59:59
 A.D.2021-01-03	AM08:30:00	A.D..2021-01-03 A.M.08:30:00
 A.D.2021-07-03	PM06:30:00	A.D..2021-07-03 P.M.18:30:00
 #
+# Test FF
+#
+SELECT TO_CHAR('2025-10-11 12:13:14.123456', 'YYYY-MM-DD HH:MM:SS.FF');
+TO_CHAR('2025-10-11 12:13:14.123456', 'YYYY-MM-DD HH:MM:SS.FF')
+2025-10-11 12:10:14.123456
+SELECT TO_CHAR('2025-10-11 12:13:14.123456', 'YYYY-MM-DD HH:MM:SS.FF6');
+TO_CHAR('2025-10-11 12:13:14.123456', 'YYYY-MM-DD HH:MM:SS.FF6')
+2025-10-11 12:10:14.123456
+SELECT TO_CHAR('2025-10-11 12:13:14.123456', 'YYYY-MM-DD HH:MM:SS.FF5');
+TO_CHAR('2025-10-11 12:13:14.123456', 'YYYY-MM-DD HH:MM:SS.FF5')
+2025-10-11 12:10:14.12345
+#
+# Test DDD, I*
+#
+select c3,to_char(c3, 'DDD') from t_to_char1 where c0 = 3;
+c3	to_char(c3, 'DDD')
+2021-01-03 08:30:00	003
+select c3,to_char(c3, 'I') from t_to_char1 where c0 = 3;
+c3	to_char(c3, 'I')
+2021-01-03 08:30:00	0
+select c3,to_char(c3, 'I-MM') from t_to_char1 where c0 = 3;
+c3	to_char(c3, 'I-MM')
+2021-01-03 08:30:00	0-01
+select c3,to_char(c3, 'IY') from t_to_char1 where c0 = 3;
+c3	to_char(c3, 'IY')
+2021-01-03 08:30:00	20
+select c3,to_char(c3, 'IYY-MM') from t_to_char1 where c0 = 3;
+c3	to_char(c3, 'IYY-MM')
+2021-01-03 08:30:00	020-01
+select c3, to_char(c3, 'IYYY-IW') from t_to_char1 where c0 between 3 and 4;
+c3	to_char(c3, 'IYYY-IW')
+2021-01-03 08:30:00	2020-53
+2021-07-03 18:30:00	2021-26
+select to_char("2001-01-01", "IYYY-IW");
+to_char("2001-01-01", "IYYY-IW")
+2001-1
+#
 # test format without order
 #
 SELECT TO_CHAR(c1, 'MM-YYYY-DD') AS C1, TO_CHAR(c2, 'HH:SS:MI') AS C2, TO_CHAR(c3, 'DD-YY-MM MI:SS:HH24') AS C3 FROM t_to_char1;
@@ -275,6 +312,10 @@ select to_char(c3, 'YYYY&DDD') from t_to_char1 where c0 = 1;
 ERROR HY000: Invalid argument error: date format not recognized at &DDD in function to_char.
 select to_char(c3, 'xxYYYY-DD') from t_to_char1 where c0 = 1;
 ERROR HY000: Invalid argument error: date format not recognized at xxYYYY-D in function to_char.
+SELECT TO_CHAR('2025-10-11 12:13:14.123456', 'YYYY-MM-DD HH:MM:SS.FF7');
+ERROR HY000: Invalid argument error: date format not recognized at 7 in function to_char.
+SELECT TO_CHAR('2025-10-11 12:13:14.123456', 'YYYY-MM-DD HH:MM:SS.FF0');
+ERROR HY000: Invalid argument error: date format not recognized at 0 in function to_char.
 SET character_set_client='latin1';
 SET character_set_connection='latin1';
 SET character_set_results='latin1';
@@ -289,10 +330,10 @@ to_char(c3, 'YYYYYYYYYYYYYYY')
 202120212021021
 select to_char(c3, 'YYYYYYYYYYYYYYYDDDDDD') from t_to_char1;
 to_char(c3, 'YYYYYYYYYYYYYYYDDDDDD')
-100010001000000010101
-999999999999999313131
-202120212021021030303
-202120212021021030303
+100010001000000001001
+999999999999999365365
+202120212021021003003
+202120212021021184184
 #
 # oracle max length is 144
 #
@@ -325,19 +366,13 @@ ERROR 42000: Incorrect parameter count in the call to native function 'to_char'
 #
 # oracle support format but mariadb does not support
 #
-select to_char(c3, 'DDD') from t_to_char1 where c0 = 1;
-ERROR HY000: Invalid argument error: date format not recognized at D in function to_char.
 select to_char(c3, 'D') from t_to_char1 where c0 = 1;
 ERROR HY000: Invalid argument error: date format not recognized at D in function to_char.
 select to_char(c3, 'DS') from t_to_char1 where c0 = 1;
 ERROR HY000: Invalid argument error: date format not recognized at DS in function to_char.
-select to_char(c3, 'IY') from t_to_char1 where c0 = 1;
-ERROR HY000: Invalid argument error: date format not recognized at IY in function to_char.
-select to_char(c3, 'IYYY') from t_to_char1 where c0 = 1;
-ERROR HY000: Invalid argument error: date format not recognized at IYYY in function to_char.
 #
 # test for first argument data type
-# 
+#
 select to_char(1, 'yyyy');
 ERROR HY000: Invalid argument error: data type of first argument must be type date/datetime/time or string in function to_char.
 select to_char(1.1, 'yyyy');

mysql-test/suite/compat/oracle/r/func_to_date-ucs2.result

@@ -0,0 +1,15 @@
+#
+# MDEV-19683 Add support for Oracle TO_DATE()
+#
+SET NAMES utf8mb3;
+SET time_zone=_latin1'+03:00';
+SET timestamp=1100000000;
+SELECT TO_DATE('1920я12',convert('YYYY"я"MM' using ucs2)) AS c;
+c
+1920-12-09 00:00:00
+SELECT TO_DATE(convert('1920я12' using ucs2),'YYYY"я"MM') AS c;
+c
+1920-12-09 00:00:00
+SELECT TO_DATE(convert('1920я12' using ucs2),convert('YYYY"я"MM' using ucs2)) AS c;
+c
+1920-12-09 00:00:00