I need Automatically change

hi
I need how to change this Automatically in sql server

my table structure and Data like this
=====================================
Select * from Tbl_Tesss
=======================
id amount
1 150
2 200
3 300
4 400

My need datawise change i think set constraint and Trigger may be reach this issue

suppose i am using this select query today july 22 i need no change the
amount field but when i will execute this select query every sunday or
after 3 days i will execute this sql query i need update the amount value 150+100 = 250 how to reach this

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