The idea is to be able to get the number of the week in a function in ORACLE but that it will always return the same values regardless of the language configuration so as not to give wrong calculations in the dates,
for example Spanish:
L M M J V S D
1 2 3 4 5 6 7
English:
D L M M j V S
1 2 3 4 5 6 7
The function I have for this is:
to_number(to_char(parametro_fecha,'D'))
The function to validate this always in the same language is validated with the language configuration in the TO_CHAR
to_number(TO_CHAR(TO_DATE(p_fecha, 'DD/MM/YYYY'), 'D', 'NLS_DATE_LANGUAGE=ENGLISH'))
ENGLISH is placed if you want Sunday to be equal to 1
or
SPANISH if you want the day Monday to be equal to 1
to_number(TO_CHAR(TO_DATE(p_fecha, 'DD/MM/YYYY'), 'D', 'NLS_DATE_LANGUAGE=SPANISH'))