Log Analytics Query Column Does Not Exist Yet

Question

Hello,

I am setting up a query on Log Analytics to be used with an Azure Alert.

My problem is that the column is only created once a certain activity happens on the resource, so the query works if the event has already happened, however, if I am creating new resources, the query fails because it cannot find the column.

So this is my query:

AzureDiagnostics  
| where OperationName contains "SecretNearExpiry"  
| extend eventGridEventProperties_data_ObjectName_s

The column eventGridEventProperties_data_ObjectName_s only gets created once an expired secret has occurred, so if this event has not occured, I am presented with:

'extend' operator: Failed to resolve scalar expression named 'eventGridEventProperties_data_ObjectName_s' Request id: 89b5e121-1b11-44b3-95a9-b38bf1125326

How can I make this query ignore the missing column, because I can only deploy my alert at the minute if there is already a expiry secret? I need some sort of if statement to only extend if the column exists.