Goodmorning everyone,
first of all I would like to explain my problem, taking into account the fact that I am a beginner with databases and this platform:
I'll start by explaining which are the lists in Sharepoint that are used as a database for the App in PowerApps.
- there is a "Customers database" list containing all the names of the customers, with their main information.
- there is a "Key Contacts" list in which all the contacts relating to a specific customer are present
- and so on...
the main problem is that by creating the lists, each Costumers (in the Costumers database) will have an ID, and within the Key Contacts, each Contact will have another ID ...
however a customer can have multiple contacts, so I thought of putting a secondary ID in the Key Contacts list, the problem is that it should be updated manually every time, making the costumer ID (Costumers Database) equal to the new secondary ID in the Key Contact, but doing so would be inconvenient ... I wanted to ask you: is there an automatic way to correlate the IDs in the two lists?
Trying to work around this problem, I thought of inserting a formula, in which I match not the IDs, but the names… to bypass the problem, but it gives me this error (maybe I have wrong the syntax):

App screen:

List in SharePoint:

I wanted to ask you for a hand in this regard, both for the first case, and (possibly if not possible), for the second.
Thank you!
Matteo.