日期比较 returns 异常结果 - SQL Oracle
Date comparison returns unusual result - SQL Oracle
我有一个table的结构:
+---------+--------------+-----------------+---------------+-------+------+
| week_no | long_week_no | week_start_date | week_end_date | month | year |
+---------+--------------+-----------------+---------------+-------+------+
| 1 | 1A | 01/01/2015 | 03/01/2015 | JAN | 2015 |
| 1 | 1B | 04/01/2015 | 10/01/2015 | JAN | 2015 |
| 2 | 2 | 11/01/2015 | 17/01/2015 | JAN | 2015 |
| 3 | 3 | 18/01/2015 | 24/01/2015 | JAN | 2015 |
| .. | .. | .. | .. | .. | .. |
| 51 | 51 | 14/12/2014 | 20/12/2015 | DEC | 2014 |
+---------+--------------+-----------------+---------------+-------+------+
当我运行下面的语句:
SELECT *
FROM loy_period
WHERE To_date('15/04/2015', 'DD/MM/YYYY') BETWEEN
To_date(week_start_date, 'DD/MM/YYYY') AND
To_date(week_end_date, 'DD/MM/YYYY');
和
SELECT *
FROM loy_period
WHERE To_date('15/04/2015', 'DD/MM/YYYY') BETWEEN
week_start_date AND
week_end_date;
return如下:
+---------+--------------+-----------------+---------------+-------+------+
| week_no | long_week_no | week_start_date | week_end_date | month | year |
+---------+--------------+-----------------+---------------+-------+------+
| 51 | 51 | 14/12/2014 | 20/12/2015 | DEC | 2014 |
| 1 | 1A | 01/01/2015 | 03/01/2015 | JAN | 2015 |
+---------+--------------+-----------------+---------------+-------+------+
并且当我 运行 它与任何日期时,它会 return 正确的周期 除了 week_no 51 记录!
我很困惑为什么会这样。 week_start_date
和 week_end_date
两列均为 date
.
类型
Fiddle 按预期工作。
它非常适合我正确使用TO_DATE和DATE值。
切勿在 DATE 上使用 TO_DATE,它将 隐式转换它变成字符串,然后使用特定于语言环境的 NLS 格式 .
返回日期
'01/01/2015'
不是日期,而是字符串。您必须使用 TO_DATE 将其显式转换为 DATE。
看看会发生什么:
SQL> explain plan for select * from dual where to_date(sysdate) > to_date(sysdate -1);
Explained.
SQL> select * from table(dbms_xplan.display);
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
Plan hash value: 3752461848
---------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
---------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 2 | 2 (0)| 00:00:01 |
|* 1 | FILTER | | | | | |
| 2 | TABLE ACCESS FULL| DUAL | 1 | 2 | 2 (0)| 00:00:01 |
---------------------------------------------------------------------------
Predicate Information (identified by operation id):
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
---------------------------------------------------
1 - filter(TO_DATE(TO_CHAR(SYSDATE@!))>TO_DATE(TO_CHAR(SYSDATE@!-1)))
14 rows selected.
SQL>
因此,实际应用的过滤器是 filter(TO_DATE(TO_CHAR(SYSDATE@!)) 由于隐含的,您将得到不正确的输出基于区域特定 NLS 格式的转换。
无论如何,现在回到你原来的问题。
例如,
假设您的数据如下:
设置:
SQL> CREATE TABLE t
2 (week_no VARCHAR2(2), long_week_no VARCHAR2(2), week_start_date DATE, week_end_date DATE, mnth VARCHAR2(3), yr VARCHAR2(4))
3 ;
Table created.
SQL>
SQL>
SQL> INSERT ALL
2 INTO t (week_no, long_week_no, week_start_date, week_end_date, mnth, yr)
3 VALUES ('1', '1A', TO_DATE('01/01/2015','DD/MM/YYYY'), TO_DATE('03/01/2015','DD/MM/YYYY'), 'JAN', '2015')
4 INTO t (week_no, long_week_no, week_start_date, week_end_date, mnth, yr)
5 VALUES ('1', '1B', TO_DATE('04/01/2015','DD/MM/YYYY'), TO_DATE('10/01/2015','DD/MM/YYYY'), 'JAN', '2015')
6 INTO t (week_no, long_week_no, week_start_date, week_end_date, mnth, yr)
7 VALUES ('2', '2', TO_DATE('11/01/2015','DD/MM/YYYY'), TO_DATE('17/01/2015','DD/MM/YYYY'), 'JAN', '2015')
8 INTO t (week_no, long_week_no, week_start_date, week_end_date, mnth, yr)
9 VALUES ('3', '3', TO_DATE('18/01/2015','DD/MM/YYYY'), TO_DATE('24/01/2015','DD/MM/YYYY'), 'JAN', '2015')
10 INTO t (week_no, long_week_no, week_start_date, week_end_date, mnth, yr)
11 VALUES ('51', '51', TO_DATE('20/12/2014','DD/MM/YYYY'), TO_DATE('26/12/2015','DD/MM/YYYY'), 'DEC', '2014')
12 SELECT * FROM dual
13 ;
5 rows created.
SQL>
SQL> COMMIT;
Commit complete.
SQL>
Table:
SQL> SELECT * FROM t;
WE LO WEEK_STAR WEEK_END_ MNT YR
-- -- --------- --------- --- ----
1 1A 01-JAN-15 03-JAN-15 JAN 2015
1 1B 04-JAN-15 10-JAN-15 JAN 2015
2 2 11-JAN-15 17-JAN-15 JAN 2015
3 3 18-JAN-15 24-JAN-15 JAN 2015
51 51 20-DEC-14 26-DEC-15 DEC 2014
SQL>
查询以根据 DATE 范围过滤行:
SQL> SELECT *
2 FROM t
3 WHERE To_date('15/01/2015', 'DD/MM/YYYY') BETWEEN
4 week_start_date AND
5 week_end_date;
WE LO WEEK_STAR WEEK_END_ MNT YR
-- -- --------- --------- --- ----
2 2 11-JAN-15 17-JAN-15 JAN 2015
51 51 20-DEC-14 26-DEC-15 DEC 2014
SQL>
我有一个table的结构:
+---------+--------------+-----------------+---------------+-------+------+ | week_no | long_week_no | week_start_date | week_end_date | month | year | +---------+--------------+-----------------+---------------+-------+------+ | 1 | 1A | 01/01/2015 | 03/01/2015 | JAN | 2015 | | 1 | 1B | 04/01/2015 | 10/01/2015 | JAN | 2015 | | 2 | 2 | 11/01/2015 | 17/01/2015 | JAN | 2015 | | 3 | 3 | 18/01/2015 | 24/01/2015 | JAN | 2015 | | .. | .. | .. | .. | .. | .. | | 51 | 51 | 14/12/2014 | 20/12/2015 | DEC | 2014 | +---------+--------------+-----------------+---------------+-------+------+
当我运行下面的语句:
SELECT *
FROM loy_period
WHERE To_date('15/04/2015', 'DD/MM/YYYY') BETWEEN
To_date(week_start_date, 'DD/MM/YYYY') AND
To_date(week_end_date, 'DD/MM/YYYY');
和
SELECT *
FROM loy_period
WHERE To_date('15/04/2015', 'DD/MM/YYYY') BETWEEN
week_start_date AND
week_end_date;
return如下:
+---------+--------------+-----------------+---------------+-------+------+ | week_no | long_week_no | week_start_date | week_end_date | month | year | +---------+--------------+-----------------+---------------+-------+------+ | 51 | 51 | 14/12/2014 | 20/12/2015 | DEC | 2014 | | 1 | 1A | 01/01/2015 | 03/01/2015 | JAN | 2015 | +---------+--------------+-----------------+---------------+-------+------+
并且当我 运行 它与任何日期时,它会 return 正确的周期 除了 week_no 51 记录!
我很困惑为什么会这样。 week_start_date
和 week_end_date
两列均为 date
.
Fiddle 按预期工作。
它非常适合我正确使用TO_DATE和DATE值。
切勿在 DATE 上使用 TO_DATE,它将 隐式转换它变成字符串,然后使用特定于语言环境的 NLS 格式 .
返回日期
'01/01/2015'
不是日期,而是字符串。您必须使用 TO_DATE 将其显式转换为 DATE。
看看会发生什么:
SQL> explain plan for select * from dual where to_date(sysdate) > to_date(sysdate -1);
Explained.
SQL> select * from table(dbms_xplan.display);
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
Plan hash value: 3752461848
---------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
---------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 2 | 2 (0)| 00:00:01 |
|* 1 | FILTER | | | | | |
| 2 | TABLE ACCESS FULL| DUAL | 1 | 2 | 2 (0)| 00:00:01 |
---------------------------------------------------------------------------
Predicate Information (identified by operation id):
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
---------------------------------------------------
1 - filter(TO_DATE(TO_CHAR(SYSDATE@!))>TO_DATE(TO_CHAR(SYSDATE@!-1)))
14 rows selected.
SQL>
因此,实际应用的过滤器是 filter(TO_DATE(TO_CHAR(SYSDATE@!)) 由于隐含的,您将得到不正确的输出基于区域特定 NLS 格式的转换。
无论如何,现在回到你原来的问题。
例如,
假设您的数据如下:
设置:
SQL> CREATE TABLE t
2 (week_no VARCHAR2(2), long_week_no VARCHAR2(2), week_start_date DATE, week_end_date DATE, mnth VARCHAR2(3), yr VARCHAR2(4))
3 ;
Table created.
SQL>
SQL>
SQL> INSERT ALL
2 INTO t (week_no, long_week_no, week_start_date, week_end_date, mnth, yr)
3 VALUES ('1', '1A', TO_DATE('01/01/2015','DD/MM/YYYY'), TO_DATE('03/01/2015','DD/MM/YYYY'), 'JAN', '2015')
4 INTO t (week_no, long_week_no, week_start_date, week_end_date, mnth, yr)
5 VALUES ('1', '1B', TO_DATE('04/01/2015','DD/MM/YYYY'), TO_DATE('10/01/2015','DD/MM/YYYY'), 'JAN', '2015')
6 INTO t (week_no, long_week_no, week_start_date, week_end_date, mnth, yr)
7 VALUES ('2', '2', TO_DATE('11/01/2015','DD/MM/YYYY'), TO_DATE('17/01/2015','DD/MM/YYYY'), 'JAN', '2015')
8 INTO t (week_no, long_week_no, week_start_date, week_end_date, mnth, yr)
9 VALUES ('3', '3', TO_DATE('18/01/2015','DD/MM/YYYY'), TO_DATE('24/01/2015','DD/MM/YYYY'), 'JAN', '2015')
10 INTO t (week_no, long_week_no, week_start_date, week_end_date, mnth, yr)
11 VALUES ('51', '51', TO_DATE('20/12/2014','DD/MM/YYYY'), TO_DATE('26/12/2015','DD/MM/YYYY'), 'DEC', '2014')
12 SELECT * FROM dual
13 ;
5 rows created.
SQL>
SQL> COMMIT;
Commit complete.
SQL>
Table:
SQL> SELECT * FROM t;
WE LO WEEK_STAR WEEK_END_ MNT YR
-- -- --------- --------- --- ----
1 1A 01-JAN-15 03-JAN-15 JAN 2015
1 1B 04-JAN-15 10-JAN-15 JAN 2015
2 2 11-JAN-15 17-JAN-15 JAN 2015
3 3 18-JAN-15 24-JAN-15 JAN 2015
51 51 20-DEC-14 26-DEC-15 DEC 2014
SQL>
查询以根据 DATE 范围过滤行:
SQL> SELECT *
2 FROM t
3 WHERE To_date('15/01/2015', 'DD/MM/YYYY') BETWEEN
4 week_start_date AND
5 week_end_date;
WE LO WEEK_STAR WEEK_END_ MNT YR
-- -- --------- --------- --- ----
2 2 11-JAN-15 17-JAN-15 JAN 2015
51 51 20-DEC-14 26-DEC-15 DEC 2014
SQL>