[ monetdb-Bugs-2814614 ] SQL: BC leap years handled incorrectly

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Bugs item #2814614, was opened at 2009-06-30 16:05
Message generated for change (Settings changed) made by boncz
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Category: SQL/Core
Group: SQL "stable"
>Status: Closed
>Resolution: Invalid
>Priority: 2
Private: No
Submitted By: gbalint (g2balint)
Assigned to: Peter Boncz (boncz)
Summary: SQL: BC leap years handled incorrectly

Initial Comment:
MonetDB handles BC timestamps, however it fails on feb 29 dates in leap years.

For a non-leap year, subtracting 1 from a 03-01 timestamps works:

sql>select cast('-4-03-01' as timestamp)-1;
+----------------------------+
| sql_sub_single_value       |
+============================+
| -4-02-28 23:59:59.000000   |
+----------------------------+
1 tuple

But for a leap year it returns nil:

sql>select cast('-5-03-01' as timestamp)-1;
+----------------------------+
| sql_sub_single_value       |
+============================+
| nil 23:59:59.000000        |
+----------------------------+
1 tuple

You also can not instantiate it explicitly:

sql>select cast('-5-02-29' as timestamp)-1;
!SQLException:timestamp:conversion of string '-5-02-29' failed


----------------------------------------------------------------------

>Comment By: Peter Boncz (boncz)
Date: 2009-11-11 15:31

Message:
BC years are a concept that is hardly definable, as the concept of year and
uniform time certainly was unknown in that age.

My take is that BC years are not supported by MonetDB/SQL.


----------------------------------------------------------------------

Comment By: Stefan Manegold (stmane)
Date: 2009-08-14 14:11

Message:
tagged subject

----------------------------------------------------------------------

Comment By: Niels Nes (nielsnes)
Date: 2009-08-06 23:08

Message:
this is a problem of the mtime (monettime) module. When converting the
string representation into internal values, there is a compensation for the
non existing 'year zero'. This somehow changes -4 into year -3 etc. passing
this to the original module writer.

----------------------------------------------------------------------

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