Welcome to the forums.
So let me first recommend that when you are asking for help avoid these things
1. Telling us about ChatGPT or anything like that
2. Explaining in words, without sharing details (pictures, steps, information that we won't know)
3. Long paragraphs about random stuff :-)
4. Make sure to include exact technology being used (don't just say database, explain what platform SharePoint, Dataverse, Azure SQL, Oracle etc as it all impacts the suggestions we make)
What I want to do is help you both to get what you need, but for myself, to get you thinking not in terms of coding, but in how you write business process steps and details because that will help you with doing Searches etc. for answers that already cover what you want. Just think if you were going to hire one of us, what would the process be that you need us to build, nothing more.
So, can you please just explain the business process step by step. With as concise as possible details what things means (like what is an expiry date). What is your hope that this will do.
I am assuming that it's like this
1. Someone enters data somewhere
2. The system checks if the dates are good / bad whatever
3. It can either stop them right then, or it can do some automated check after the fact and block it... email them to fix it, email you to fix it
Also, and possibly
4. You have dates that are already there, and you need to run a 1-time process to resolve those existing or, you simply want a completely automated process.
In the context of Power Platform under the covers you have data, processes and Ux. Some of those processes are Ai created/managed, some are manual, some are done via data.
In the most simplistic example imagine this.
You have a SharePoint List, or you have a Dataverse Table and you want to check if after someone enters a date is valid, OR you want to have an automated process that runs every day to check on dates.
Automated Example
1. You would create an Automated Flow, with a Trigger for
Either
a) when an item is created or modified (SharePoint)
b) when an item is (and then you select the scope) for a Dataverse Action
2. Read the Date Value for Expiry and see if it fits some range. this would be a Condition, or a Compose, but in the end its something that can return a boolean true or false, if this date matches your criteria. Now if you want to specifically say its too early, or its too late, or its missed or whatever, then you have to focus on using Complex "if" expressions, or multi-level conditions
3. After #2 produces you something this is where you decide (using a condition), inside the Yes side of the Condition (meaning it Met your criteria, maybe you do nothing) and in the No side maybe you email, or delete the record, or copy it to some other table or whatever you want.
Scheduled Example
The difference between Scheduled and Automated is that automated is going to tell the Flow instance that runs exactly what record it is talking about, where-as a Scheduled flow has to actually query and iterate through all the rows to decide IF it should act on this record.
1. Create a Scheduled Flow (set the days/hours/minutes of when to run)
2. Use a List rows / Get Items depending on SharePoint or Dataverse or Excel
3. Add an Apply to each which is a looping action for all the rows that came back in #2
From here the code is nearly identical to Option 1
use a condition to check the Fields of Data to see if it meets your condition
Yes Side
-Probably do nothing
No Side
-Do something
And Scene.
Please let me know what other questions you have and details you can share.
Cheers