Re: Day of week question

Tom Lane wrote:

>"Andrew Dunstan" <andrew@dunslane.net> writes:
>  
>
>>Looks like it is caused by the switch to the Gregorian calendar in 1752,
>>when 11 days were chopped out of September ( in England and America -
>>elsewhere anywhere between Oct 1582 and early 20th century).
>>    
>>
>
>There was some discussion awhile back about extending PG's date code
>to know about the Julian calendar, but the idea pretty much died when
>it was pointed out that you'd need locale-specific information about
>exactly when the switchover occurred.
>
>SQL99 makes it perfectly clear that all datetime values are Gregorian,
>for example we find wording like this in the <literal> section:
>
>         9) If <date value> is specified, then it is interpreted as a date
>            in the Gregorian calendar.
>
>So one could argue that the existing PG behavior is SQL-compliant.
>I tend to regard this as an easy out, but nonetheless it's an available
>defense if someone tries to beat you up about PG's "wrong answers".
>  
>
Perhaps we need a function or two to convert pre-gregorian dates to 
gregorian dates and vice versa, with the cutover date either a 
configuration variable (default the 1752 date) or a parameter of the 
function.

e.g. j_to_g('1700-01-01'::date) => '1700-01-13'      j_to_g('1800-01-01'::date) => '1800-01-01'

just a thought

andrew