I Need Help To Write Queries

[Mostafa Baghi]

hello,
i want build a event for check disabled discounts used and remove them from payments for my website https://www.onwebsite.ir/

i need help to write query for get from database where create_date < now date
and remove all results found

please help me for witch query i write?

and the second i want write a wordpress plugin for auto backup from database

and my question is how can i get backup from database by php or queries codes?

and the third i need some where for learn queries as pro if you can please help me....