how to validate dates in Oracle Apex 18.1

Hi Team,

I'm working on requirement where I've to use to dates items start date and end date. These dates should store in the database.

I'm trying to use validation on the end date as it shouldn't be lesser than start date. end date < start date then error message. but this is not showing any error message when I use it in the validation. when I change it to end date > start date then it's throwing error even for valid cases. Please suggest me to use proper approach in Apex for dates validation.

Regards,

Syed Shakir