Comparing date with sysdate in oracle

问题

I have a column which is of "DATE" type and I want to run a query on it comparing it with sysdate.

But I am getting following error, Can someone please let me know what I am missing here?

SQL> select distinct file_name as r 
     from table_1 
     where view_day >= TO_DATE(SYSDATE-10, 'YYYY/MM/DD');

ERROR at line 1:
ORA-01858: a non-numeric character was found where a numeric was expected

回答1:

You shouldn't use to_date on a date, To_date is for casting a varchar to date, not a date.
If you do use the function to_date on a date, then oracle will refer to it as a string according to nls_date_format which may vary in different environments.
As @jonearles said, if you want to remove the time in sysdate then use TRUNC

回答2:

USE:

select distinct file_name as r 
from table_1 
where view_day >= TRUNC(SYSDATE-10)

回答3:

Error shows that a VIEW_DAY column is varchar so you need to convert DATE to String. Use TO_CHAR or convert VIEW_DAY to date type.

来源：https://stackoverflow.com/questions/9147393/comparing-date-with-sysdate-in-oracle