甲骨文:无效月份 [英] Oracle: not a valid month
问题描述
我有一个包含以下字段的表格:
I have a table with the following fields:
报告(表名) Rep_Date(日期) Rep_Time(日期)
Reports (table name) Rep_Date (date) Rep_Time (date)
Rep_Time字段的值类似于"01/01/1753 07:30:00",即时间部分是相关的.我写了以下查询:
The Rep_Time field has values like '01/01/1753 07:30:00' i.e. the time part is relevant. I have written the following query:
select Reports.pid, MaxDate from Reports
INNER JOIN (
select pid, max(TO_DATE(TO_CHAR(REP_DATE, 'DD/MM/YYYY')
|| TO_CHAR(REP_TIME, 'HH24:MI:SS'), 'DD/MM/YYYY HH24:MI:SS')) As MaxDate
from reports
group by pid
) ReportMaxDate
on Reports.PID = ReportMaxDate.PID
AND To_Date(To_Char(MaxDate, 'DD/MM/YYYY')) = REP_DATE
WHERE REPORTS.PID=61
查询的派生表部分运行,但是当我运行整个查询时,出现错误:无效月份".为什么是这样?
The derived table part of the query runs, but when I run the entire query I get an error: "not a valid month". Why is this?
为了帮助调试它;如果我运行以下查询:
In order to help debug this; if I run the following query:
select rep_date, rep_time from reports where pid=61 and rownum=1
我得到:
Rep_Date = 01/04/2009
Rep_Time = 01/01/1753 13:00:00
更新15:58 我现在可以执行以下查询:
UPDATE 15:58 I am now able to execute the following query:
select Reports.pid, MaxDate from Reports
INNER JOIN (
select pid, max(TO_DATE(TO_CHAR(REP_DATE, 'DD/MM/YYYY')
|| TO_CHAR(REP_TIME, 'HH24:MI:SS'), 'DD/MM/YYYY HH24:MI:SS')) As MaxDate
from reports group by pid
) ReportMaxDate
on Reports.PID = ReportMaxDate.PID
AND to_date(to_char(maxdate,'MM/DD/YYYY'),'MM/DD/YYYY') = REP_DATE
WHERE REPORTS.PID=61
但是,我需要在WHERE
子句中再添加一条语句,以比较MaxDate和rep_time的时间部分:to_date(to_char(maxdate,'MM/DD/YYYY'),'MM/DD/YYYY') = REP_DATE
不起作用.
However, I need to add one more statement to the WHERE
clause comparing the time part of MaxDate to rep_time: to_date(to_char(maxdate,'MM/DD/YYYY'),'MM/DD/YYYY') = REP_DATE
does not work.
推荐答案
1.
To_Date(To_Char(MaxDate, 'DD/MM/YYYY')) = REP_DATE
是引起问题的原因.当您使用不带时间格式的to_date时,oracle将使用当前会话的NLS格式进行转换,在您的情况下,该格式可能不是"DD/MM/YYYY".检查一下...
is causing the issue. when you use to_date without the time format, oracle will use the current sessions NLS format to convert, which in your case might not be "DD/MM/YYYY". Check this...
SQL> select sysdate from dual;
SYSDATE
---------
26-SEP-12
Which means my session's setting is DD-Mon-YY
SQL> select to_char(sysdate,'MM/DD/YYYY') from dual;
TO_CHAR(SY
----------
09/26/2012
SQL> select to_date(to_char(sysdate,'MM/DD/YYYY')) from dual;
select to_date(to_char(sysdate,'MM/DD/YYYY')) from dual
*
ERROR at line 1:
ORA-01843: not a valid month
SQL> select to_date(to_char(sysdate,'MM/DD/YYYY'),'MM/DD/YYYY') from dual;
TO_DATE(T
---------
26-SEP-12
2.
更重要的是,为什么要转换为char然后再转换为日期,而不是直接进行比较
More importantly, Why are you converting to char and then to date, instead of directly comparing
MaxDate = REP_DATE
如果要在比较之前忽略MaxDate中的时间分量,则应使用..
If you want to ignore the time component in MaxDate before comparision, you should use..
trunc(MaxDate ) = rep_date
相反.
==更新:基于更新的问题.
==Update : based on updated question.
Rep_Date = 01/04/2009 Rep_Time = 01/01/1753 13:00:00
我认为问题更加复杂.如果rep_time仅是时间,则不能将其作为日期存储在数据库中.它必须是时间间隔的字符串或日期,或者必须是以秒为单位的数字(感谢Alex,请参阅
I think the problem is more complex. if rep_time is intended to be only time, then you cannot store it in the database as a date. It would have to be a string or date to time interval or numerically as seconds (thanks to Alex, see this) . If possible, I would suggest using one column rep_date that has both the date and time and compare it to the max date column directly.
如果它是一个正在运行的系统,并且您无法控制repdate,则可以尝试此操作.
If it is a running system and you have no control over repdate, you could try this.
trunc(rep_date) = trunc(maxdate) and
to_char(rep_date,'HH24:MI:SS') = to_char(maxdate,'HH24:MI:SS')
无论哪种方式,时间存储都不正确(正如您可以从1753年看到的那样),并且可能还会出现其他问题.
Either way, the time is being stored incorrectly (as you can tell from the year 1753) and there could be other issues going forward.
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