Dear Tom,
> After all that about numbering centuries and millenia correctly,
> why does CVS tip still give me
>
> regression=# select extract(century from now());
> date_part
> -----------
> 20
> (1 row)
> [ ... looks in code ... ]
>
> Apparently it's because you fixed only timestamp_part, and not
> timestamptz_part. I'm not too sure about what timestamp_trunc or
> timestamptz_trunc should do, but they may be wrong as well.
Sigh... as usual, what is not tested does not work:-(
> Could we have a more complete patch?
Please find a submission attached. I hope it really fixes all decade,
century and millenium issues for extract and *_trunc functions on interval
and other timestamp types. If someone could check that the results
are reasonnable, it would be great.
I indeed overlooked the fact that there were two functions. The patch
fixes the code so that both variants agree.
I added comments to interval extractions, because it relies on the C
division to have a negative remainder: -7/10 = 0 and remains -7.
As for *_trunc functions, I have chosen to put the first year of the
century or millennium: -100, 1, 101... 1001 2001 etc. Indeed, I don't
think it would make sense to put 2000 (last year of the 2nd millennium)
for rounding all years of the third millenium.
I also fixed the code so that all decades last 10 years and decade 199
means the 1990's.
I have added some tests that are relevant to deal with tricky cases. The
formula may be simplified, but all these cases must pass. Please keep
them.
Have a nice day,
--
Fabien Coelho - [EMAIL PROTECTED]
*** ./src/backend/utils/adt/timestamp.c.orig Fri Jun 4 15:50:58 2004
--- ./src/backend/utils/adt/timestamp.c Tue Aug 10 16:31:41 2004
***************
*** 2727,2737 ****
fsec = 0;
break;
case DTK_MILLENNIUM:
! tm->tm_year = (tm->tm_year / 1000) * 1000;
case DTK_CENTURY:
! tm->tm_year = (tm->tm_year / 100) * 100;
case DTK_DECADE:
! tm->tm_year = (tm->tm_year / 10) * 10;
case DTK_YEAR:
tm->tm_mon = 1;
case DTK_QUARTER:
--- 2727,2752 ----
fsec = 0;
break;
case DTK_MILLENNIUM:
! /* see comments in timestamptz_trunc */
! if (tm->tm_year > 0)
! tm->tm_year = ((tm->tm_year+999) / 1000) *
1000 - 999;
! else
! tm->tm_year = - ((999 - (tm->tm_year-1))/1000)
* 1000 + 1;
case DTK_CENTURY:
! /* see comments in timestamptz_trunc */
! if (tm->tm_year > 0)
! tm->tm_year = ((tm->tm_year+99) / 100) * 100 -
99;
! else
! tm->tm_year = - ((99 - (tm->tm_year-1))/100) *
100 + 1;
case DTK_DECADE:
! /* see comments in timestamptz_trunc */
! if (val != DTK_MILLENNIUM && val != DTK_CENTURY)
! {
! if (tm->tm_year > 0)
! tm->tm_year = (tm->tm_year / 10) * 10;
! else
! tm->tm_year = - ((8-(tm->tm_year-1)) /
10) * 10;
! }
case DTK_YEAR:
tm->tm_mon = 1;
case DTK_QUARTER:
***************
*** 2830,2841 ****
tm->tm_sec = 0;
fsec = 0;
break;
case DTK_MILLENNIUM:
! tm->tm_year = (tm->tm_year / 1000) * 1000;
case DTK_CENTURY:
! tm->tm_year = (tm->tm_year / 100) * 100;
case DTK_DECADE:
! tm->tm_year = (tm->tm_year / 10) * 10;
case DTK_YEAR:
tm->tm_mon = 1;
case DTK_QUARTER:
--- 2845,2877 ----
tm->tm_sec = 0;
fsec = 0;
break;
+ /* one may consider DTK_THOUSAND and DTK_HUNDRED... */
case DTK_MILLENNIUM:
! /* truncating to the millennium? what is this supposed
to mean?
! * let us put the first year of the millennium...
! * i.e. -1000, 1, 1001, 2001...
! */
! if (tm->tm_year > 0)
! tm->tm_year = ((tm->tm_year+999) / 1000) *
1000 - 999;
! else
! tm->tm_year = - ((999 - (tm->tm_year-1))/1000)
* 1000 + 1;
case DTK_CENTURY:
! /* truncating to the century? as above: -100, 1,
101... */
! if (tm->tm_year > 0)
! tm->tm_year = ((tm->tm_year+99) / 100) * 100 -
99 ;
! else
! tm->tm_year = - ((99 - (tm->tm_year-1))/100) *
100 + 1;
case DTK_DECADE:
! /* truncating to the decade? first year of the decade.
! * must not be applied if year was truncated before!
! */
! if (val != DTK_MILLENNIUM && val != DTK_CENTURY)
! {
! if (tm->tm_year > 0)
! tm->tm_year = (tm->tm_year / 10) * 10;
! else
! tm->tm_year = - ((8-(tm->tm_year-1)) /
10) * 10;
! }
case DTK_YEAR:
tm->tm_mon = 1;
case DTK_QUARTER:
***************
*** 2923,2932 ****
--- 2959,2971 ----
switch (val)
{
case DTK_MILLENNIUM:
+ /* caution: C division may have negative
remainder */
tm->tm_year = (tm->tm_year / 1000) * 1000;
case DTK_CENTURY:
+ /* caution: C division may have negative
remainder */
tm->tm_year = (tm->tm_year / 100) * 100;
case DTK_DECADE:
+ /* caution: C division may have negative
remainder */
tm->tm_year = (tm->tm_year / 10) * 10;
case DTK_YEAR:
tm->tm_mon = 0;
***************
*** 3221,3227 ****
break;
case DTK_DECADE:
! result = (tm->tm_year / 10);
break;
case DTK_CENTURY:
--- 3260,3273 ----
break;
case DTK_DECADE:
! /* what is a decade wrt dates?
! * let us assume that decade 199 is 1990 thru 1999...
! * decade 0 starts on year 1 BC, and -1 is 11 BC thru
2 BC...
! */
! if (tm->tm_year>=0)
! result = (tm->tm_year / 10);
! else
! result = -((8-(tm->tm_year-1)) / 10);
break;
case DTK_CENTURY:
***************
*** 3232,3238 ****
if (tm->tm_year > 0)
result = ((tm->tm_year+99) / 100);
else
! /* caution: C division may yave negative
remainder */
result = - ((99 - (tm->tm_year-1))/100);
break;
--- 3278,3284 ----
if (tm->tm_year > 0)
result = ((tm->tm_year+99) / 100);
else
! /* caution: C division may have negative
remainder */
result = - ((99 - (tm->tm_year-1))/100);
break;
***************
*** 3445,3459 ****
break;
case DTK_DECADE:
! result = (tm->tm_year / 10);
break;
case DTK_CENTURY:
! result = (tm->tm_year / 100);
break;
case DTK_MILLENNIUM:
! result = (tm->tm_year / 1000);
break;
case DTK_JULIAN:
--- 3491,3517 ----
break;
case DTK_DECADE:
! /* see comments in timestamp_part */
! if (tm->tm_year>0)
! result = (tm->tm_year / 10);
! else
! result = - ((8-(tm->tm_year-1)) / 10);
break;
case DTK_CENTURY:
! /* see comments in timestamp_part */
! if (tm->tm_year > 0)
! result = ((tm->tm_year+99) / 100);
! else
! result = - ((99 - (tm->tm_year-1))/100);
break;
case DTK_MILLENNIUM:
! /* see comments in timestamp_part */
! if (tm->tm_year > 0)
! result = ((tm->tm_year+999) / 1000);
! else
! result = - ((999 - (tm->tm_year-1))/1000);
break;
case DTK_JULIAN:
***************
*** 3606,3619 ****
--- 3664,3680 ----
break;
case DTK_DECADE:
+ /* caution: C division may have negative
remainder */
result = (tm->tm_year / 10);
break;
case DTK_CENTURY:
+ /* caution: C division may have negative
remainder */
result = (tm->tm_year / 100);
break;
case DTK_MILLENNIUM:
+ /* caution: C division may have negative
remainder */
result = (tm->tm_year / 1000);
break;
*** ./src/test/regress/expected/date.out.orig Mon Apr 12 14:25:37 2004
--- ./src/test/regress/expected/date.out Tue Aug 10 16:41:12 2004
***************
*** 930,932 ****
--- 930,1081 ----
3
(1 row)
+ --
+ -- decade
+ --
+ SELECT EXTRACT(DECADE FROM DATE '1994-12-25'); -- 199
+ date_part
+ -----------
+ 199
+ (1 row)
+
+ SELECT EXTRACT(DECADE FROM DATE '0010-01-01'); -- 1
+ date_part
+ -----------
+ 1
+ (1 row)
+
+ SELECT EXTRACT(DECADE FROM DATE '0009-12-31'); -- 0
+ date_part
+ -----------
+ 0
+ (1 row)
+
+ SELECT EXTRACT(DECADE FROM DATE '0001-01-01 BC'); -- 0
+ date_part
+ -----------
+ 0
+ (1 row)
+
+ SELECT EXTRACT(DECADE FROM DATE '0002-12-31 BC'); -- -1
+ date_part
+ -----------
+ -1
+ (1 row)
+
+ SELECT EXTRACT(DECADE FROM DATE '0011-01-01 BC'); -- -1
+ date_part
+ -----------
+ -1
+ (1 row)
+
+ SELECT EXTRACT(DECADE FROM DATE '0012-12-31 BC'); -- -2
+ date_part
+ -----------
+ -2
+ (1 row)
+
+ --
+ -- some other types:
+ --
+ -- on a timestamp.
+ SELECT EXTRACT(CENTURY FROM NOW())>=21 AS True; -- true
+ true
+ ------
+ t
+ (1 row)
+
+ SELECT EXTRACT(CENTURY FROM TIMESTAMP '1970-03-20 04:30:00.00000'); -- 20
+ date_part
+ -----------
+ 20
+ (1 row)
+
+ -- on an interval
+ SELECT EXTRACT(CENTURY FROM INTERVAL '100 y'); -- 1
+ date_part
+ -----------
+ 1
+ (1 row)
+
+ SELECT EXTRACT(CENTURY FROM INTERVAL '99 y'); -- 0
+ date_part
+ -----------
+ 0
+ (1 row)
+
+ SELECT EXTRACT(CENTURY FROM INTERVAL '-99 y'); -- 0
+ date_part
+ -----------
+ 0
+ (1 row)
+
+ SELECT EXTRACT(CENTURY FROM INTERVAL '-100 y'); -- -1
+ date_part
+ -----------
+ -1
+ (1 row)
+
+ --
+ -- test trunc function!
+ --
+ SELECT DATE_TRUNC('MILLENNIUM', TIMESTAMP '1970-03-20 04:30:00.00000'); -- 1001
+ date_trunc
+ --------------------------
+ Thu Jan 01 00:00:00 1001
+ (1 row)
+
+ SELECT DATE_TRUNC('MILLENNIUM', DATE '1970-03-20'); -- 1001-01-01
+ date_trunc
+ ------------------------------
+ Thu Jan 01 00:00:00 1001 PST
+ (1 row)
+
+ SELECT DATE_TRUNC('CENTURY', TIMESTAMP '1970-03-20 04:30:00.00000'); -- 1901
+ date_trunc
+ --------------------------
+ Tue Jan 01 00:00:00 1901
+ (1 row)
+
+ SELECT DATE_TRUNC('CENTURY', DATE '1970-03-20'); -- 1901
+ date_trunc
+ ------------------------------
+ Tue Jan 01 00:00:00 1901 PST
+ (1 row)
+
+ SELECT DATE_TRUNC('CENTURY', DATE '2004-08-10'); -- 2001-01-01
+ date_trunc
+ ------------------------------
+ Mon Jan 01 00:00:00 2001 PST
+ (1 row)
+
+ SELECT DATE_TRUNC('CENTURY', DATE '0002-02-04'); -- 0001-01-01
+ date_trunc
+ ------------------------------
+ Mon Jan 01 00:00:00 0001 PST
+ (1 row)
+
+ SELECT DATE_TRUNC('CENTURY', DATE '0055-08-10 BC'); -- 0100-01-01 BC
+ date_trunc
+ ---------------------------------
+ Tue Jan 01 00:00:00 0100 PST BC
+ (1 row)
+
+ SELECT DATE_TRUNC('DECADE', DATE '1993-12-25'); -- 1990-01-01
+ date_trunc
+ ------------------------------
+ Mon Jan 01 00:00:00 1990 PST
+ (1 row)
+
+ SELECT DATE_TRUNC('DECADE', DATE '0004-12-25'); -- 0001-01-01 BC
+ date_trunc
+ ---------------------------------
+ Sat Jan 01 00:00:00 0001 PST BC
+ (1 row)
+
+ SELECT DATE_TRUNC('DECADE', DATE '0002-12-31 BC'); -- 0011-01-01 BC
+ date_trunc
+ ---------------------------------
+ Mon Jan 01 00:00:00 0011 PST BC
+ (1 row)
+
*** ./src/test/regress/sql/date.sql.orig Mon Apr 12 14:25:37 2004
--- ./src/test/regress/sql/date.sql Tue Aug 10 16:40:13 2004
***************
*** 235,237 ****
--- 235,271 ----
SELECT EXTRACT(MILLENNIUM FROM DATE '2001-01-01'); -- 3
-- next test to be fixed on the turn of the next millennium;-)
SELECT EXTRACT(MILLENNIUM FROM CURRENT_DATE); -- 3
+ --
+ -- decade
+ --
+ SELECT EXTRACT(DECADE FROM DATE '1994-12-25'); -- 199
+ SELECT EXTRACT(DECADE FROM DATE '0010-01-01'); -- 1
+ SELECT EXTRACT(DECADE FROM DATE '0009-12-31'); -- 0
+ SELECT EXTRACT(DECADE FROM DATE '0001-01-01 BC'); -- 0
+ SELECT EXTRACT(DECADE FROM DATE '0002-12-31 BC'); -- -1
+ SELECT EXTRACT(DECADE FROM DATE '0011-01-01 BC'); -- -1
+ SELECT EXTRACT(DECADE FROM DATE '0012-12-31 BC'); -- -2
+ --
+ -- some other types:
+ --
+ -- on a timestamp.
+ SELECT EXTRACT(CENTURY FROM NOW())>=21 AS True; -- true
+ SELECT EXTRACT(CENTURY FROM TIMESTAMP '1970-03-20 04:30:00.00000'); -- 20
+ -- on an interval
+ SELECT EXTRACT(CENTURY FROM INTERVAL '100 y'); -- 1
+ SELECT EXTRACT(CENTURY FROM INTERVAL '99 y'); -- 0
+ SELECT EXTRACT(CENTURY FROM INTERVAL '-99 y'); -- 0
+ SELECT EXTRACT(CENTURY FROM INTERVAL '-100 y'); -- -1
+ --
+ -- test trunc function!
+ --
+ SELECT DATE_TRUNC('MILLENNIUM', TIMESTAMP '1970-03-20 04:30:00.00000'); -- 1001
+ SELECT DATE_TRUNC('MILLENNIUM', DATE '1970-03-20'); -- 1001-01-01
+ SELECT DATE_TRUNC('CENTURY', TIMESTAMP '1970-03-20 04:30:00.00000'); -- 1901
+ SELECT DATE_TRUNC('CENTURY', DATE '1970-03-20'); -- 1901
+ SELECT DATE_TRUNC('CENTURY', DATE '2004-08-10'); -- 2001-01-01
+ SELECT DATE_TRUNC('CENTURY', DATE '0002-02-04'); -- 0001-01-01
+ SELECT DATE_TRUNC('CENTURY', DATE '0055-08-10 BC'); -- 0100-01-01 BC
+ SELECT DATE_TRUNC('DECADE', DATE '1993-12-25'); -- 1990-01-01
+ SELECT DATE_TRUNC('DECADE', DATE '0004-12-25'); -- 0001-01-01 BC
+ SELECT DATE_TRUNC('DECADE', DATE '0002-12-31 BC'); -- 0011-01-01 BC
---------------------------(end of broadcast)---------------------------
TIP 4: Don't 'kill -9' the postmaster
