SharePoint List - track changes with MS Flow

Question

I have SharePoint List with several columns, which I want to track for changes, and log those changes into another List. Below is example (in Excel, for simplicity) for subset of 2 columns ("->" deontes changing from X to Y):

I have just started to learn SharePoint Flows, and I am a bit stacked here. What I have learned so far is this:

• I should start with SharePoint Trigger "When item is created or modified" modified"
• Use Action "Get Items" to pull data from MyChangelogList

Should I first create and populate MyChangelogList (as first/initial copy of MyList), and then compare it (what Flow Action to use?) with MyList? What Flow Actions to use to update values in MyChangelogList in format as above?

Important Remark: I have requirement not to modify MyList. All changes must be logged into separate list i.e. MyChangelogList.

Answer 1

1.Create a flow with MyList, choose "When item is created or modified" as flow's trigger, you do not need to compare Mylist with MyChangelogList, When the item in MyList modified, flow will run automatically.

2.In the update item action, set date as 2020-01-01 -> 2020-01-15.

Answer 2

My approach was to have a current and previous field in my primary list. When Current <> Previous - it's because Current was changed. (Previous is not visible in any view or edit form.) In your flow - compare curr_Field = prev_Field. If not equal - gather the list items from the List Item Changed/Modified group. Create a new list item for your logging list. Assign values. Then... update the original record so that prev_Field = curr_Field.