SQL 查询两个日期之差大于某个值时删除记录

Question

I would like to delete records when the difference between SYSDATE and a TIMESTAMP (6) field of my table is greater than 10 days. I have created the following query:

select (SYSDATE - myDate) as difference from myTable where difference > 10;

but i get the following error:

00904. 00000 -  "%s: invalid identifier"

am i creating the query correctly?

Answer 1

am i creating the query correctly?

No, you cannot refer to an alias in the SELECT clause in the filter condition of the same statement.

Additionally, when you subtract a TIMESTAMP from a DATE you will get the result as an INTERVAL data type; so you need to compare on that rather than a NUMBER (which would be the result if you compared DATE - DATE ).

You want:

SELECT SYSDATE - myDate as difference
FROM   myTable
WHERE  SYSDATE - myDate > INTERVAL '10' DAY;

db<>fiddle here