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Re: [GENERAL] FM format modifier does not remove leading zero from year
Command: select to_char(DATE'2009-1-1','FMDD.FMMM.FMYY') Result observed: 1.1.09 Result expected: 1.1.9 How to fix ? Andrus.
On Saturday 02 January 2010 10:14:07 am Andrus wrote: > Command: > > select to_char(DATE'2009-1-1','FMDD.FMMM.FMYY') > > Result observed: > > 1.1.09 > > Result expected: > > 1.1.9 > > How to fix ? > > Andrus. From what I could see in the source code (src/backend/utils/adt/formatting.c) the year portion of the string is not run through the FM modifier. A fix would mean a patch to the above AFAIK. -- Adrian Klaver aklaver(at)comcast(dot)net
Adrian Klaver <aklaver(at)comcast(dot)net> writes: > From what I could see in the source code > (src/backend/utils/adt/formatting.c) the year portion of the string is > not run through the FM modifier. A fix would mean a patch to the above > AFAIK. Should it be? Can anyone check how this works on Oracle? regards, tom lane
On 1/5/2010 10:54 AM, Tom Lane wrote: > Adrian Klaver<aklaver(at)comcast(dot)net> writes: >> From what I could see in the source code >> (src/backend/utils/adt/formatting.c) the year portion of the string is >> not run through the FM modifier. A fix would mean a patch to the above >> AFAIK. > > Should it be? Can anyone check how this works on Oracle? > Oracle states clearly in the SQL Reference manual: "A modifier can appear in a format model more than once. In such a case, each subsequent occurrence toggles the effects of the modifier." I get the following results: select to_char(DATE'2009-1-1','FMDD.FMMM.FMYY') from dual; 1.01.9 select to_char(DATE'2009-1-1','FM DD.MM.YY') from dual 1.1.9 -- Guy Rouillier
Guy Rouillier <guyr-ml1(at)burntmail(dot)com> writes: > Oracle states clearly in the SQL Reference manual: > "A modifier can appear in a format model more than once. In such a case, > each subsequent occurrence toggles the effects of the modifier." *Toggles* the effect of the modifier? Egad, what drunken idiot chose that specification? That's certainly not how PG is interpreting the FM modifier --- we suppose it applies to just the specifier it's attached to. Still, we generally assume that Oracle is the authoritative reference for how to_char() ought to behave, so maybe we should hold our noses and change it. Problem is that this would inevitably break practically every existing use of to_date with FM :-( (not to mention the other modifiers, which I suppose behave that way too?) Anyway, your example clearly shows that FM ought to strip leading zeroes in YY, so that change ought to get made. regards, tom lane
On 1/6/2010 3:29 PM, Tom Lane wrote: > Guy Rouillier<guyr-ml1(at)burntmail(dot)com> writes: >> Oracle states clearly in the SQL Reference manual: > >> "A modifier can appear in a format model more than once. In such a case, >> each subsequent occurrence toggles the effects of the modifier." > > *Toggles* the effect of the modifier? Egad, what drunken idiot chose > that specification? Eh, tomato, tomahto. If you assume that someone will strip leading zeroes consistently, the Oracle approach makes sense. That would be a reasonable assumption to make; why would I strip the zero off the month but leave it on the day? So, in the unusual case that you want to do such a thing, you are asked to use a second occurrence of FM to turn zero suppression back off. -- Guy Rouillier
Guy Rouillier wrote: > On 1/6/2010 3:29 PM, Tom Lane wrote: > > Guy Rouillier<guyr-ml1(at)burntmail(dot)com> writes: > >> Oracle states clearly in the SQL Reference manual: > > > >> "A modifier can appear in a format model more than once. In such a case, > >> each subsequent occurrence toggles the effects of the modifier." > > > > *Toggles* the effect of the modifier? Egad, what drunken idiot chose > > that specification? > > Eh, tomato, tomahto. If you assume that someone will strip leading > zeroes consistently, the Oracle approach makes sense. That would be a > reasonable assumption to make; why would I strip the zero off the month > but leave it on the day? So, in the unusual case that you want to do > such a thing, you are asked to use a second occurrence of FM to turn > zero suppression back off. I have developed the attached patch which implements FM control of YYY, YY, and Y specifications. I also documented that we do not match Oracle's toggle behavior. There are a few effects on regression test output which are part of this patch. -- Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us EnterpriseDB http://enterprisedb.com + If your life is a hard drive, Christ can be your backup. +
Attachment: /pgpatches/tochar_fm
Description: text/x-diff (8.1 KB)
Description: text/x-diff (8.1 KB)
Bruce Momjian wrote: > Guy Rouillier wrote: > > On 1/6/2010 3:29 PM, Tom Lane wrote: > > > Guy Rouillier<guyr-ml1(at)burntmail(dot)com> writes: > > >> Oracle states clearly in the SQL Reference manual: > > > > > >> "A modifier can appear in a format model more than once. In such a case, > > >> each subsequent occurrence toggles the effects of the modifier." > > > > > > *Toggles* the effect of the modifier? Egad, what drunken idiot chose > > > that specification? > > > > Eh, tomato, tomahto. If you assume that someone will strip leading > > zeroes consistently, the Oracle approach makes sense. That would be a > > reasonable assumption to make; why would I strip the zero off the month > > but leave it on the day? So, in the unusual case that you want to do > > such a thing, you are asked to use a second occurrence of FM to turn > > zero suppression back off. > > I have developed the attached patch which implements FM control of YYY, > YY, and Y specifications. I also documented that we do not match > Oracle's toggle behavior. There are a few effects on regression test > output which are part of this patch. What's the point of not following Oracle here, since this is solely an Oracle compatibility function? -- Alvaro Herrera http://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support
Alvaro Herrera <alvherre(at)commandprompt(dot)com> writes: > What's the point of not following Oracle here, since this is solely an > Oracle compatibility function? Changing FM's behavior like that will break approximately every user of to_char() ... regards, tom lane
Tom Lane wrote: > Alvaro Herrera <alvherre(at)commandprompt(dot)com> writes: > > What's the point of not following Oracle here, since this is solely an > > Oracle compatibility function? > > Changing FM's behavior like that will break approximately every user > of to_char() ... I would love to know why we are finding out about this incompatibility only in 2010, years after we implemented this. Is no one porting multi-specification "FM" to_char() strings from Oracle to PostgreSQL? -- Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us EnterpriseDB http://enterprisedb.com + If your life is a hard drive, Christ can be your backup. +
Applied. --------------------------------------------------------------------------- Bruce Momjian wrote: > Guy Rouillier wrote: > > On 1/6/2010 3:29 PM, Tom Lane wrote: > > > Guy Rouillier<guyr-ml1(at)burntmail(dot)com> writes: > > >> Oracle states clearly in the SQL Reference manual: > > > > > >> "A modifier can appear in a format model more than once. In such a case, > > >> each subsequent occurrence toggles the effects of the modifier." > > > > > > *Toggles* the effect of the modifier? Egad, what drunken idiot chose > > > that specification? > > > > Eh, tomato, tomahto. If you assume that someone will strip leading > > zeroes consistently, the Oracle approach makes sense. That would be a > > reasonable assumption to make; why would I strip the zero off the month > > but leave it on the day? So, in the unusual case that you want to do > > such a thing, you are asked to use a second occurrence of FM to turn > > zero suppression back off. > > I have developed the attached patch which implements FM control of YYY, > YY, and Y specifications. I also documented that we do not match > Oracle's toggle behavior. There are a few effects on regression test > output which are part of this patch. > > -- > Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us > EnterpriseDB http://enterprisedb.com > > + If your life is a hard drive, Christ can be your backup. + [ text/x-diff is unsupported, treating like TEXT/PLAIN ] > Index: doc/src/sgml/func.sgml > =================================================================== > RCS file: /cvsroot/pgsql/doc/src/sgml/func.sgml,v > retrieving revision 1.500 > diff -c -c -r1.500 func.sgml > *** doc/src/sgml/func.sgml 1 Feb 2010 15:38:21 -0000 1.500 > --- doc/src/sgml/func.sgml 6 Feb 2010 21:14:41 -0000 > *************** > *** 5174,5180 **** > <para> > <literal>FM</literal> suppresses leading zeroes and trailing blanks > that would otherwise be added to make the output of a pattern be > ! fixed-width. > </para> > </listitem> > > --- 5174,5184 ---- > <para> > <literal>FM</literal> suppresses leading zeroes and trailing blanks > that would otherwise be added to make the output of a pattern be > ! fixed-width. In <productname>PostgreSQL</productname>, > ! <literal>FM</literal> modifies only the next specification, while in > ! Oracle <literal>FM</literal> affects all subsequent > ! specifications, and repeated <literal>FM</literal> modifiers > ! toggle fill mode on and off. > </para> > </listitem> > > Index: src/backend/utils/adt/formatting.c > =================================================================== > RCS file: /cvsroot/pgsql/src/backend/utils/adt/formatting.c,v > retrieving revision 1.162 > diff -c -c -r1.162 formatting.c > *** src/backend/utils/adt/formatting.c 2 Jan 2010 16:57:53 -0000 1.162 > --- src/backend/utils/adt/formatting.c 6 Feb 2010 21:14:42 -0000 > *************** > *** 515,520 **** > --- 515,521 ---- > #define S_th(_s) (((_s) & DCH_S_th) ? 1 : 0) > #define S_TH_TYPE(_s) (((_s) & DCH_S_TH) ? TH_UPPER : TH_LOWER) > > + /* Oracle toggles FM behavior, we don't; see docs. */ > #define S_FM(_s) (((_s) & DCH_S_FM) ? 1 : 0) > #define S_SP(_s) (((_s) & DCH_S_SP) ? 1 : 0) > #define S_TM(_s) (((_s) & DCH_S_TM) ? 1 : 0) > *************** > *** 2411,2438 **** > break; > case DCH_YYY: > case DCH_IYY: > ! snprintf(buff, sizeof(buff), "%03d", > n->key->id == DCH_YYY ? > ADJUST_YEAR(tm->tm_year, is_interval) : > ADJUST_YEAR(date2isoyear(tm->tm_year, > tm->tm_mon, tm->tm_mday), > is_interval)); > i = strlen(buff); > ! strcpy(s, buff + (i - 3)); > if (S_THth(n->suffix)) > str_numth(s, s, S_TH_TYPE(n->suffix)); > s += strlen(s); > break; > case DCH_YY: > case DCH_IY: > ! snprintf(buff, sizeof(buff), "%02d", > n->key->id == DCH_YY ? > ADJUST_YEAR(tm->tm_year, is_interval) : > ADJUST_YEAR(date2isoyear(tm->tm_year, > tm->tm_mon, tm->tm_mday), > is_interval)); > i = strlen(buff); > ! strcpy(s, buff + (i - 2)); > if (S_THth(n->suffix)) > str_numth(s, s, S_TH_TYPE(n->suffix)); > s += strlen(s); > --- 2412,2441 ---- > break; > case DCH_YYY: > case DCH_IYY: > ! snprintf(buff, sizeof(buff), "%0*d", > ! S_FM(n->suffix) ? 0 : 3, > n->key->id == DCH_YYY ? > ADJUST_YEAR(tm->tm_year, is_interval) : > ADJUST_YEAR(date2isoyear(tm->tm_year, > tm->tm_mon, tm->tm_mday), > is_interval)); > i = strlen(buff); > ! strcpy(s, buff + (i > 3 ? i - 3 : 0)); > if (S_THth(n->suffix)) > str_numth(s, s, S_TH_TYPE(n->suffix)); > s += strlen(s); > break; > case DCH_YY: > case DCH_IY: > ! snprintf(buff, sizeof(buff), "%0*d", > ! S_FM(n->suffix) ? 0 : 2, > n->key->id == DCH_YY ? > ADJUST_YEAR(tm->tm_year, is_interval) : > ADJUST_YEAR(date2isoyear(tm->tm_year, > tm->tm_mon, tm->tm_mday), > is_interval)); > i = strlen(buff); > ! strcpy(s, buff + (i > 2 ? i - 2 : 0)); > if (S_THth(n->suffix)) > str_numth(s, s, S_TH_TYPE(n->suffix)); > s += strlen(s); > *************** > *** 2446,2452 **** > tm->tm_mon, tm->tm_mday), > is_interval)); > i = strlen(buff); > ! strcpy(s, buff + (i - 1)); > if (S_THth(n->suffix)) > str_numth(s, s, S_TH_TYPE(n->suffix)); > s += strlen(s); > --- 2449,2455 ---- > tm->tm_mon, tm->tm_mday), > is_interval)); > i = strlen(buff); > ! strcpy(s, buff + (i > 1 ? i - 1 : 0)); > if (S_THth(n->suffix)) > str_numth(s, s, S_TH_TYPE(n->suffix)); > s += strlen(s); > Index: src/test/regress/expected/timestamp.out > =================================================================== > RCS file: /cvsroot/pgsql/src/test/regress/expected/timestamp.out,v > retrieving revision 1.40 > diff -c -c -r1.40 timestamp.out > *** src/test/regress/expected/timestamp.out 22 Mar 2009 01:12:32 -0000 1.40 > --- src/test/regress/expected/timestamp.out 6 Feb 2010 21:14:44 -0000 > *************** > *** 1063,1070 **** > | 1,997 1997 997 97 7 20 1 2 7 45 14 6 2450494 > | 1,997 1997 997 97 7 20 1 2 7 46 15 7 2450495 > | 1,997 1997 997 97 7 20 1 2 7 47 16 1 2450496 > ! | 0,097 97 097 97 7 1 1 2 7 47 16 3 1686042 > ! | 0,097 97 097 97 7 1 1 2 7 47 16 7 1756536 > | 0,597 597 597 97 7 6 1 2 7 47 16 5 1939157 > | 1,097 1097 097 97 7 11 1 2 7 47 16 3 2121778 > | 1,697 1697 697 97 7 17 1 2 7 47 16 7 2340924 > --- 1063,1070 ---- > | 1,997 1997 997 97 7 20 1 2 7 45 14 6 2450494 > | 1,997 1997 997 97 7 20 1 2 7 46 15 7 2450495 > | 1,997 1997 997 97 7 20 1 2 7 47 16 1 2450496 > ! | 0,097 97 97 97 7 1 1 2 7 47 16 3 1686042 > ! | 0,097 97 97 97 7 1 1 2 7 47 16 7 1756536 > | 0,597 597 597 97 7 6 1 2 7 47 16 5 1939157 > | 1,097 1097 097 97 7 11 1 2 7 47 16 3 2121778 > | 1,697 1697 697 97 7 17 1 2 7 47 16 7 2340924 > *************** > *** 1561,1568 **** > | 1997 997 97 7 7 47 5 > | 1997 997 97 7 7 48 6 > | 1997 997 97 7 7 49 7 > ! | 97 097 97 7 7 44 2 > ! | 97 097 97 7 7 48 6 > | 597 597 97 7 7 46 4 > | 1097 097 97 7 7 44 2 > | 1697 697 97 7 7 48 6 > --- 1561,1568 ---- > | 1997 997 97 7 7 47 5 > | 1997 997 97 7 7 48 6 > | 1997 997 97 7 7 49 7 > ! | 97 97 97 7 7 44 2 > ! | 97 97 97 7 7 48 6 > | 597 597 97 7 7 46 4 > | 1097 097 97 7 7 44 2 > | 1697 697 97 7 7 48 6 > Index: src/test/regress/expected/timestamptz.out > =================================================================== > RCS file: /cvsroot/pgsql/src/test/regress/expected/timestamptz.out,v > retrieving revision 1.34 > diff -c -c -r1.34 timestamptz.out > *** src/test/regress/expected/timestamptz.out 22 Mar 2009 01:12:32 -0000 1.34 > --- src/test/regress/expected/timestamptz.out 6 Feb 2010 21:14:44 -0000 > *************** > *** 1148,1155 **** > | 1,997 1997 997 97 7 20 1 2 7 45 14 6 2450494 > | 1,997 1997 997 97 7 20 1 2 7 46 15 7 2450495 > | 1,997 1997 997 97 7 20 1 2 7 47 16 1 2450496 > ! | 0,097 97 097 97 7 1 1 2 7 47 16 3 1686042 > ! | 0,097 97 097 97 7 1 1 2 7 47 16 7 1756536 > | 0,597 597 597 97 7 6 1 2 7 47 16 5 1939157 > | 1,097 1097 097 97 7 11 1 2 7 47 16 3 2121778 > | 1,697 1697 697 97 7 17 1 2 7 47 16 7 2340924 > --- 1148,1155 ---- > | 1,997 1997 997 97 7 20 1 2 7 45 14 6 2450494 > | 1,997 1997 997 97 7 20 1 2 7 46 15 7 2450495 > | 1,997 1997 997 97 7 20 1 2 7 47 16 1 2450496 > ! | 0,097 97 97 97 7 1 1 2 7 47 16 3 1686042 > ! | 0,097 97 97 97 7 1 1 2 7 47 16 7 1756536 > | 0,597 597 597 97 7 6 1 2 7 47 16 5 1939157 > | 1,097 1097 097 97 7 11 1 2 7 47 16 3 2121778 > | 1,697 1697 697 97 7 17 1 2 7 47 16 7 2340924 > *************** > *** 1655,1662 **** > | 1997 997 97 7 7 47 5 > | 1997 997 97 7 7 48 6 > | 1997 997 97 7 7 49 7 > ! | 97 097 97 7 7 44 2 > ! | 97 097 97 7 7 48 6 > | 597 597 97 7 7 46 4 > | 1097 097 97 7 7 44 2 > | 1697 697 97 7 7 48 6 > --- 1655,1662 ---- > | 1997 997 97 7 7 47 5 > | 1997 997 97 7 7 48 6 > | 1997 997 97 7 7 49 7 > ! | 97 97 97 7 7 44 2 > ! | 97 97 97 7 7 48 6 > | 597 597 97 7 7 46 4 > | 1097 097 97 7 7 44 2 > | 1697 697 97 7 7 48 6 > > -- > Sent via pgsql-hackers mailing list (pgsql-hackers(at)postgresql(dot)org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-hackers -- Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us EnterpriseDB http://enterprisedb.com + If your life is a hard drive, Christ can be your backup. +