选择最大或最晚日期的问题 [英] Problem to select max or latest date

问题描述

我想根据最新日期显示一些细节。但是，我有问题。它说Oracle.DataAccess.Client.OracleException：ORA-00923：在预期的地方找不到FROM关键字



我尝试过：



以下是查询：



SELECT DISTINCT CCSMASTERLISTREVNO，CCSREVCONTENT，CCSPREPAREDREV，

CCSREVEFFECTIVATEATE



来自CCS2_TBL_MASTERLIST



在哪里CCSEQUIPMENTDPMT =：DPMT



和CCSMASTERLISTREVNO< =：REVNO



和CCSREVEFFECTIVEDATE =



（SELECT MAX（TO_CHAR（CCSREVEFFECTIVEDATE，'dd / MM / yyyy'））



来自CCS2_TBL_MASTERLIST）



ORDER BY CCSMASTERLISTREVNO DESC;

解决方案

（ SELECT  MAX（TO_CHAR（CCSREVEFFECTIVEDATE，'  dd / MM / yyyy'））<  -  extra）here 
 
  FROM  CCS2_TBL_MASTERLIST）<  - 此   end     SELECT  

你有一个上面第一行的额外结束括号。



为什么要将日期转换为字符串以找到最大值？

< blockquote>添加到理查德所说的内容：当您将日期比较为字符串时，您使用字符串比较。这意味着两个字符串逐字符进行检查，整个比较的结果基于找到的第一个不同的字符对。

在您的情况下，这意味着11/01/2018之前1977年12月1日和01/01/2048之后



你必须存储和比较日期作为日期，而不是字符串 - 否则你会得到一些非常奇怪的看似结果。

Hi, I want to display some details based on the latest date. But, I have problem with it. It say that "Oracle.DataAccess.Client.OracleException: ORA-00923: FROM keyword not found where expected"

What I have tried:

Below are the query:

SELECT DISTINCT CCSMASTERLISTREVNO, CCSREVCONTENT, CCSPREPAREDREV,
CCSREVEFFECTIVEDATE

FROM CCS2_TBL_MASTERLIST

WHERE CCSEQUIPMENTDPMT = :DPMT

AND CCSMASTERLISTREVNO <= :REVNO

AND CCSREVEFFECTIVEDATE =

( SELECT MAX(TO_CHAR(CCSREVEFFECTIVEDATE,'dd/MM/yyyy'))

FROM CCS2_TBL_MASTERLIST )

ORDER BY CCSMASTERLISTREVNO DESC;

解决方案

( SELECT MAX(TO_CHAR(CCSREVEFFECTIVEDATE,'dd/MM/yyyy'))<- extra ) here

FROM CCS2_TBL_MASTERLIST ) <- this is the end of the SELECT

You have an extra closing parenthesis on the first line above.

And why are you converting your dates to character strings to find the maximum value?

To add to what Richard says: when you compare dates as strings, you use a string comparison. Which means that the two strings are examined character by character and the result of the whole comparison is based on the first different pair of characters found.
Which in your case means that 11/01/2018 comes before 12/01/1977 and after 01/01/2048

You must store and compare dates as dates, not strings - or you will get some very odd seeming results.

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