oracle sql查詢列出上個月的所有日期

Question

伙計們我要求列出上個月的所有日期，如下所示

20101201
20101202
20101203
20101204
20101205
..
..
..
..
..
..
..
..
20101231

如果有任何比這個查詢更好的方法，請告訴我。

select TO_CHAR(TRUNC(SYSDATE,'MM')-1,'YYYYMMDD')-(level-1) as 
EACH_DATE from dual A connect by level 
< (TO_NUMBER(TO_CHAR(TRUNC(SYSDATE,'MM')-1,'DD'))+1)

另請告訴我這個查詢的問題，它說“缺少右括號”

SELECT /*+ PARALLEL (A,8) */ /*+ DRIVING_STATE */
   TO_CHAR(TRUNC(TRUNC(SYSDATE,'MM')-1,'MM'),'MONYYYY') "MONTH", TYPE AS "TRAFF",     COLUMN, A_COUN AS "A_COUNT",COST  FROM DATA_P B WHERE  EXISTS  
(  
  select TO_NUMBER(TO_CHAR(TRUNC(SYSDATE,'MM')-1,'YYYYMMDD')-(level-1))  EACH_DATE 
  from dual A connect by  level < TO_NUMBER(TO_CHAR(TRUNC(SYSDATE,'MM')-1,'DD')+1) 
  WHERE A.EACH_DATE = B.DATE  order by EACH_DATE ASC
 )

強調文字

Answer 1

聽起來你想要這樣的東西

SQL> ed
Wrote file afiedt.buf

  1  select to_char( add_months(trunc(sysdate,'MM'),-1) + level - 1,
  2                  'YYYYMMDD' )
  3    from dual
  4  connect by level <=
  5    last_day(add_months(trunc(sysdate,'MM'),-1)) -
  6    add_months(trunc(sysdate,'MM'),-1) +
  7*   1
SQL> /

TO_CHAR(
--------
20101201
20101202
20101203
20101204
20101205
20101206
20101207
20101208
20101209
20101210
20101211
20101212
20101213
20101214
20101215
20101216
20101217
20101218
20101219
20101220
20101221
20101222
20101223
20101224
20101225
20101226
20101227
20101228
20101229
20101230
20101231

31 rows selected.

Answer 2

本月：

SELECT  TO_CHAR (TRUNC (SYSDATE, 'MM'), 'YYYYMMDD')+(LEVEL - 1) each_date
FROM    DUAL a
CONNECT BY LEVEL < (TO_NUMBER (TO_CHAR (TRUNC (SYSDATE, 'MM') - 1, 'DD'))+1)

Answer 3

一些add_month肯定會讓它變得更好，就像在例如

select to_char(x,'yyyymmdd') from (
  select add_months(trunc(sysdate,'MONTH'),-1)+rownum-1 x from all_objects
) where x<trunc(sysdate,'MONTH');

Answer 4

這可能更容易理解：

select TO_CHAR(d, 'YYYYMMDD')
from (
  select ADD_MONTHS(TRUNC(SYSDATE, 'MM'), -1) + (ROWNUM - 1) d
  from DUAL connect by level <= 31
)
where d < TRUNC(SYSDATE, 'MM')

然而，“連接的水平”的方法是最清楚的，並且描述這里 ，更快的方式生成的數字序列。 我認為沒有辦法顯着改善您的查詢。

Answer 5

就右括號而言，您試圖以錯誤的方式連接字符串：

select TO_CHAR(TRUNC(SYSDATE,'MM')-1,'YYYYMMDD')-(level-1) as

應該管用：

select TO_CHAR(TRUNC(SYSDATE,'MM')-1,'YYYYMMDD') || '-' || To_Char(level-1) as

顯然你不希望連接發生。 因此，我認為你實際上想要將級別添加到TRUNC()部分

固定：

select TO_CHAR(TRUNC(SYSDATE,'MM') - 1 + level - 1,'YYYYMMDD') as 
EACH_DATE from dual A connect by level 
< (TO_NUMBER(TO_CHAR(TRUNC(SYSDATE,'MM')-1,'DD'))+1)