Comparing New and Previous Column Value in SharePoint on Item Modification via Power Automate

Context of problem:
I have a column in sharepoint list (f.e: Status) and when item is modified, I want to compare updated value (f.e "Accepted") with the previous one (f.e "Pending")

It took me few days to figure out the way which doesn't require complicated going-arounds, premium actions or hard stuff like parsing json

Final structure:

(later on Send an HTTP request to SharePoint will be renamed to HTTP and Filter array to FILTER)

As you can see - It took only 7 actions to solve this problem. Let's go!

What you should have at the beginning:

• Sharepoint list with column that you want to track. In my case it is "Status"
• At least one item

Step 1 - When an item or a file is modified

Intention: Triggering when specified column is modified (for example - Status has been changed)

Key	Value
Site Adress	Link to your sharepoint list
List or Library Name	Name of your sharepoint list
Folder name	leave blank

Step 2 - Send an HTTP request to SharePoint

IMPORTANT - Rename this action to "HTTP" (click three dots -> Rename) - Trust me, it will be useful later

Intention: Getting old states of this row

Key	Value
Site Adress	Link to your sharepoint list (the same as before)
Method	GET
Uri	/_api/web/lists/getByTitle('LIST NAME')/items(ID-OF-ITEM)/Versions?$filter=IsCurrentVersion eq false&$orderby=versionId desc&$top=1

Where:

• LIST-NAME - Is string with the Name of your list
• ID-OF-ITEM - In Power Automate select this fragment, select ID from "When an item or a file is modified" (first screen from this step)

(Optional - You don't have to read this if you are not interested what is beyond Uri stuff)

• _api/web/lists/getByTitle('LIST NAME')- Catches collection of your list
• /items(ID-OF-ITEM) - Catches all the old versions of updated item
• ?$filter=IsCurrentVersion eq false - Filtering: You don't want the current version (it is avaliable from the very first action)
• &$orderby=versionId desc&$top=1 - Sorting: You want the most previous element and only one

Step 3- Initialize variable

Intention: Data that you received have very strange form (nested array of objects) and you have to find the one column that you are interested in

Key	Value
Name	foundObj
Type	Array
Value	[]

Step 4 - Filter Array

IMPORTANT - Rename this action to "FILTER" (click three dots -> Rename) - Trust me, it will be useful later

Intention: I mentioned that received data have very strange form. You have to filter it and access necessary fields.

Click the input, select "Expression" and write the following text:

Key	Value
Array to filter	body('HTTP')['d']['results']
Choose a value (left)	contains(item(),'Status')
Choose a value (right)	true

Final effect should look like this:

Note that this fragment works only when:

• You renamed "Send an HTTP request to SharePoint" to "HTTP" (as i asked in step 2)
• You want to refer to the "Status" column. If the one you track is different - rename it

---

So far, you should have 4 actions:

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Step 5 - Set variable

Intention: Saving the data from filtering

After this step, you will have an array of one object. Job is almost done

Step 6 - Initialize Variable (to save oldStatus)

(when you add this action, Power Automate should automatically rename it to Initialize Variable 2)

Intention: Saving old status (the one before the update)

Key	Value
Name	oldStatus
Type	String
Value	body('FILTER')[0]['Status']

In order to apply this value, again, click the input and switch to "Expression"

Note that this fragment works oly when:

• You renamed "Filter array" to "FILTER" (as I asked in step 4)
• You want to refer to the "Status" column. If the one you track is different - rename it

Step 7 - Initialize variable (to save newStatus)

(when you add this action, Power Automate should automaticly rename it to Initialize Variable 3)

Intention - Saving new status (after the update)

In fact, it is only a formal step. You have to select interesting column and save it to the variable (so you eventually have two variables: oldStatus and newStatus)

All you have to do is select Status from "Send an HTTP request to SharePoint" action.

Note, that in my case Status was an option-choice, so I have to select Status Value, but it doesn't effect anything.

The final effect should look like this:

Conclusion

And that's it! You should have 2 variables: newStatus and oldStatus which contain wanted information. You can do with them whatever you want: Creating conditions, sending emails - Sky is the limit

It doesn't matter if the column will change in terms of Power Apps form or hand-change in sharepoint - This flow will work.

Please be aware of the fact, that in step 2 I fetched only last update). If you want to compare more old values - Switch &top=1 in Uri input to the number you actually want.

I also wanted to mention that my solution doesn't involve using premium actions and bases on elementary operations, so you shouldn't worry that future changes in Power Automate actions would affect integrity of this flow.

Comments

[george y]

Hi, i've followed this to a T and keep getting the error

InvalidTemplate
Unable to process template language expressions in action 'Initialize_variable_1' inputs at line '0' and column '0': 'The template language expression 'body('FILTER')[0]['Engineering Status']' cannot be evaluated because array index '0' cannot be selected from empty array. Please see aka.ms/logicexpressions for usage details.'.

for the 2nd "initialize value" ..... (your 1st one had a '1' in the name, mine didnt, my 2nd one has a '1' in the name)

[Mateusz Iwaniuk]

Hi, I will try to help you with that.

By step T I assume you mean step 6. Could you please provide a screenshot of your steps, and what is the output just of body('FILTER')[0]?

And could you also run the flow and show step by step what are the outputs of each cell? Are you sure you changed filter cell name to FILTER?

If your data is sensitive, you can blur it. I would like to see the overall JSON and keys in each step