Forum Discussion
column_if_exists throws error "The expression must be constant"
Hi, I have the below query in which I want to check if the UserAgent column exists, however I am unable to complete column_if_exists as it underlines in red "UserAgent". Hovering my mouse over it...
Trying adding quotes
| extend UserAgent_2=column_ifexists("UserAgent", " ")
| extend UserAgent_2=column_ifexists("UserAgent", " ")
This did not work as expected. Instead I used iff and it works
| extend UserAgent= iif( AdditionalDetails.key == "User-Agent", UserAgent=AdditionalDetails.value, " ")
| extend UserAgent= iif( AdditionalDetails.key == "User-Agent", UserAgent=AdditionalDetails.value, " ")
