I'm trying to create a unique id in my lists, which is exported from a MS form. But I keep getting errors.

So my logic is very simple:

Step 1: once a form is submitted, the responses will be automatically send to the list. (I created a separate flow for this and everything works perfectly in this step.)

Step 2:once a new response is created in the list, an associated unique id will be generated for this new response.(This is the second flow I'm trying to create right now.)

I want the unique id to be: DP+request date+ID. For example, if the request date of the request is 10/26/2023, and it's the third request in the list, so the unique id for this request would be DP1026202300003.If the 16th request in the list has request date 08/12/2025, then its unique id would be DP0812202500016.

Here is my flow: initialize variable

Request Form Tracker - Data Pull is the list I created in the first step, where stores all the responses.


  1. Here is the formula I use:concat('DP',formatDateTime(triggerOutputs()?['body/Request Date'],'yyyyMMdd'),formatNumber(triggerOutputs()?['body/ID'],'000000'))

2.The 'request date' is a required field in the form, which should be the same date that people submitted the form.

3.Request Form Tracker - Data Pull is the list I created in the first step, where stores all the responses.

4.'Request ID' is the name of the unique id in the list.

And here is the error I got: error message

I've also tried using the default Create date instead of the request date, but it didn't work either.

Can someone help me on this please?


1 Answer 1


The error shows you what the error is. The date field triggerOutputs()?['body/Request Date'] is empty, thus flow cannot do formatDateTime() operation with it. I recommend to use Created Date triggerOutputs()?['body/Created'], which is never null.

Working expression:


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