Re: date format WW(week number) question

I think this works, but sure there are better ways:

1. Determine first day of the last week of the year select to_date('31/12/1999','dd/mm/YYYY') - to_char(to_date('31/12/1999','dd/mm/YYYY'),'D') +1 from dual;
2. Then determine weeknumber of last week and substract (weeknumber minus 1) * 7 to get date of first day of week 1 select to_date('31/12/1999','dd/mm/YYYY') - to_char(to_date('31/12/1999','dd/mm/YYYY'),'D') +1
   • (to_char(to_date('31/12/1999','dd/mm/YYYY'),'WW') -1) *7 from dual;
3. Add 7 * weeknumberA to get first day of week A select to_date('31/12/1999','dd/mm/YYYY') - to_char(to_date('31/12/1999','dd/mm/YYYY'),'D') +1
   • (to_char(to_date('31/12/1999','dd/mm/YYYY'),'WW') -1) *7 + (40 * 7) from dual;
4. Add 6 days to get the last day of the week select to_date('31/12/1999','dd/mm/YYYY') - to_char(to_date('31/12/1999','dd/mm/YYYY'),'D') +1
   • (to_char(to_date('31/12/1999','dd/mm/YYYY'),'WW') -1) *7 + (40 * 7) + 6 from dual;
5. replace the "hard" week and year numbers by variables: select to_date('31/12/&&B','dd/mm/YYYY') - to_char(to_date('31/12/&&B','dd/mm/YYYY'),'D') +1
   • (to_char(to_date('31/12/&&B','dd/mm/YYYY'),'WW') -1) *7 + (&A * 7) + 6 from dual;

guerillot gil wrote:

> i know only the week number A and the year B.
>
> what kind of sql select query to write for obtain X the first day and Y the
> last day of the week
> with only the two parameters A and B?
>
> for example A=40 and B=1999.
>
> X=4/10/1999
> Y=10/10/1999 (in french format)
>
> thanks for help !!!
Received on Sat Sep 25 1999 - 14:41:06 CDT