Question

伙计们我需要列出上个月的所有日期，如下所示

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

请告诉我是否有比此查询更好的方法。

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)

另请告诉我这个查询的问题，它说“缺少右括号”

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
 )

强调文字

Answer 1

听起来你想要这样的东西

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

当月：

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肯定会让它变得更好，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

这可能更容易理解：

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，“按级别连接”方法是最清晰的，如here所述，更快的方式来生成数字序列。我认为没有办法显着改善您的查询。

Answer 5

就右括号而言，您试图以错误的方式连接字符串：

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

应该有效：

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

显然你不希望连接发生。因此，我认为您实际上想要将级别添加到TRUNC() - 部分

修正：

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)

oracle sql查询列出上个月的所有日期

5 个答案: