TO_CHAR(…, ‘D’)

to_char(nchar-clob-or-nclob)

to_char(datetime-or-interval)
to_char(datetime-or-interval, 'format-string')
to_char(datetime-or-interval, 'format-string', 'nlsparam')

to_char(number)
to_char(number,'format-string')
to_char(number,'format-string', 'nlsparam')

How do I get than MONDAY=1, TUESDAY=2, WEDNESDAY=3 … ?
solution1
With to_char()

alter session set nls_territory=germany;
select to_char(sysdate,’DAY D’) from dual;
TUESDAY 2

solution2
With decode()

The abbrivation of a day’s name (such as SUN, MON … can be retrieved with the format specifier DY. As to_char is sensitive to the actual nls setting, I use nls_date_language=english to make sure that the english abbreviation is returned, regardless of the nls setting.

select decode(to_char(sysdate, ‘FMDAY’, ‘NLS_DATE_LANGUAGE=american’),’MONDAY’, ’1′, ‘TUESDAY’, ’2′, ‘…’)) from dual;

solution3
With mod()
As a reference, I take monday Jan 1st, 1000.

select mod(trunc(sysdate)-date ’1000-01-01′,7)+1 from dual;

bonus )))

How do I trunc date to current monday?

trunc(date, ‘D’) or here is with my solution with 1000-01-01:

select trunc((sysdate-date ’1000-01-01′)/7)*7+date ’1000-01-01′ from dual;

thanks to jan-marcel idea, I found that one
trunc(date,’IW’) for current monday and date-trunc(date,’IW’)+1 for day number

Spelling a number

select to_char(to_date('429','J'),'Jsp') from dual;
TO_CHAR(TO_DATE('429','J
------------------------
Four Hundred Twenty-Nine

from1
from2