如何仅从 Oracle SQL Developer 的 DateTime 字段中提取时间？
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How to extract only Time from a DateTime field in Oracle SQL Developer?
提问by MontyPython
I tried To_Timestampand other methods for SQL Developer but only this one worked fine for me.
我尝试To_Timestamp了 SQL Developer 的其他方法，但只有这个方法对我有用。
Select To_Number(To_Char(DateTime_FieldName, 'HH24'))
|| ':' || to_number(to_char(DateTime_FieldName, 'MI'))
|| ':' ||to_number(to_char(DateTime_FieldName, 'SS'))
from TABLE_NAME
Is there a better solution to this?
有没有更好的解决方案？
回答by Justin Cave
Assuming your goal is to generate a string representing the time (which is what the query you posted returns despite the extraneous to_numbercalls)
假设您的目标是生成一个表示时间的字符串（这是您发布的查询返回的内容，尽管有无关的to_number调用）
SELECT to_char( <<column_name>>, 'HH24:MI:SS' )
FROM table_name
If you want to return a different data type, you'd need to tell us what data type you want to return. If, for example, you really want to return an INTERVAL DAY TO SECOND
如果要返回不同的数据类型，则需要告诉我们要返回的数据类型。例如，如果您真的想返回一个INTERVAL DAY TO SECOND
SELECT numtodsinterval( <<column name>> - trunc(<<column name>>), 'day' )
FROM table_name
