SQL> SELECT TO_CHAR(date '1982-03-09', 'DAY') day FROM dual;

DAY
---------
TUESDAY

SQL> SELECT TO_CHAR(date '1982-03-09', 'DY') day FROM dual;

DAY
---
TUE

SQL> SELECT TO_CHAR(date '1982-03-09', 'Dy') day FROM dual;

DAY
---
Tue

(请注意，查询使用的是ANSI日期文字，该文字遵循ISO-8601日期标准，并避免了日期格式的歧义.)

(Note that the queries use ANSI date literals, which follow the ISO-8601 date standard and avoid date format ambiguity.)