Trigger a flow when an Sharepoint column value CHANGES

[Anonymous]

Hi all,

I have a Boolean column of an SP list and I want to have a flow triggered whenever its boolean value CHANGES, whether it is from false to true, or from true to false. It doesn't matter which value it has been changed. How could I achieve that in the Setting | Trigger Conditions?  Please advise.

P.S. I know how to set the trigger condition to test if a column equals to a particular value; but just don't know how to handle the case described above. Thanks in advance. 

[grantjenkins]

I've created an example of how you could achieve this. Note that this assumes have major versions set on the list.

In my example I'm using a list called Courses with a column called Active using data type Yes/No.

See the full flow below. I'll go into each of the changes.

Trigger: I've used When an item or a file is modified as we don't want it to trigger when we first create our item - only when it's modified.

Next, we use Get changes for an item or a file (properties only). This allows us to see what fields have changed since the last version which exactly what you want - when your field changes from true to false, or vice versa.

The expression I've used to get the previous version number is below. It converts the Version number to a float then subtracts 1 from it.

sub(float(triggerOutputs()?['body/{VersionNumber}']), 1)

Lastly, I use the output of the last action to check if my Active field has changed since the last version.

The field I used in this example was for my column called Active:

[Anonymous]

Hello grantjenkins,

Thanks for your quick and detailed reply. 

But what I have got you, in your case:

- The flow will be fired as long as there is a modification in the list.

- Then the flow will check if the change is what you are looking for.

Your approach would work fine if the list is updated not so often; otherwise there would be performance issue ... and that is not what I really want. 

So what I really want is to have the flow triggered ONLY when the intended column value changes by setting up expressions in the Setting | Trigger Condition. You can access this by clicking the "three dots" menu of your first action "When an item or file is modified". 

Any further ideas? Thanks in advance. 

[grantjenkins]

I definitely would have suggested a Trigger condition if I could, but don't think it's possible in this instance.

The Trigger will only include information from the current version of the item so no way to compare a field to the previous value. I'll do some more digging but believe that the way I have it is the only way to check previous to current.

[ScottShearer · Accepted solution]

@Anonymous 

@grantjenkins is correct.  You cannot use a trigger condition.  You might consider storing the value a second time in an additional column.  If you did, you could use a trigger condition and then update the value in the additional column.

[Anonymous]

@ScottShearer ; @grantjenkins ,

Thanks for the input of all of you. Adding an additional column for the previously changed value is not a difficult workaround.