SQL Help !! - Oracle / ¿ª·¢

ÈçÌ⣺
  SQL code:

SELECT TO_CHAR(TO_DATE(ACCEPT_TIME, 'yyyy-mm-dd hh24:mi:ss'), 'W'),
COUNT(*)
from T_LIST
WHERE to_char(to_date(ACCEPT_TIME,'yyyy-mm-dd hh24:mi:ss'),'MM')=to_char(SYSDATE-1,'MM')
GROUP BY TO_CHAR(TO_DATE(ACCEPT_TIME, 'yyyy-mm-dd hh24:mi:ss'), 'W')
ORDER BY TO_CHAR(TO_DATE(ACCEPT_TIME, 'yyyy-mm-dd hh24:mi:ss'), 'W') ;



Ò»¸öÔµÄÖܱ¨±í µ±Ä³Ò»ÖÜûÊý¾Ýʱ Ôõô°ÑÄÇÒ»ÖÜÏÔʾ³öÀ´ ½á¹ûÏÔʾΪ0;
  T_list ÊÇÒ»¸ö²Ù×÷Á÷Ë®±í ACCEPT_TIMEÊDzÙ×÷ʱ¼ä¡£

---

ÔÚÏߵȴ𰸣¡£¡Ï£Íû¸÷λ´ó´ó °ïÏÂæ¡£¡£

---

°ï¶¥, ºöÓƼǵøøÎÒ·Ö```

---

SQL code:


SELECT null(TO_CHAR(TO_DATE(ACCEPT_TIME, 'yyyy-mm-dd hh24:mi:ss'), 'W'),0),
COUNT(*)
from T_LIST
WHERE to_char(to_date(ACCEPT_TIME,'yyyy-mm-dd hh24:mi:ss'),'MM')=to_char(SYSDATE-1,'MM')
GROUP null(TO_CHAR(TO_DATE(ACCEPT_TIME, 'yyyy-mm-dd hh24:mi:ss'), 'W'),0)
ORDER BY null(TO_CHAR(TO_DATE(ACCEPT_TIME, 'yyyy-mm-dd hh24:mi:ss'), 'W'),0) ;

---

SQL code:

--±ÊÎó,Ó¦¸ÃÊÇnvl£¨£©º¯Êý
SELECT nvl(TO_CHAR(TO_DATE(ACCEPT_TIME, 'yyyy-mm-dd hh24:mi:ss'), 'W'),0),
COUNT(*)
from T_LIST
WHERE to_char(to_d