Increment a Column value from another table

[KushagraGupta]

I have 2 tables

1.  Payments : Below are the columns
   • Student (Ref To another table also)
   • Num Of Sessions
   • Amount
   • FeeForTheMonth
2. StudentsSessionInfo : Below are the columns
   • Student
   • TotalSessionsAllowed (This value needs to be updated , once a new row is added in the above table , existing value + value from above table (Num of sessions) are to be added)
   • Month
   • Year

There will only be 1 row in StudentsSessionInfo for per student per month per year , but multiple rows per student per month in Payments table. 

I'm having difficulty in achieving the above result, please help.

[KushagraGupta]

@dbaum , please help , if possible

[nicolasfsamaja]

Sometimes I use an automation like this:

In origen table put a column called Trigger. TRUE / FALSE (default value FALSE)

Then in the automation you put that it occurs when Trigger is TRUE

The automation will be modifie a value... And then next action... Go again to Trigger and put FALSE.

This Trigger you can put a formula that change when XX change... Check some formulas of last value or sth similar