azureazure-data-explorerkqlstring-conversion

Azure Data Explorer Create a new column based on 2 columns

I have a table in Azure Data Explorer and I want to have a new string column that is the result of the concatenation of 2 string columns.

In KQL I can do it by using extend and strcat functions but I want the column to be part of the table data not just a virtual column:

TableName
| extend NewCol=strcat(Col1,"separator",Col2)

Doing the above will indeed create a new column and the value I want for the column but will not be stored as a new column in the table which is what I want.

Something like this in SQL:

ALTER TABLE Employees ADD FullName AS (FirstName + ' ' + LastName)
Solution

  • you can't ingest data into a new column in existing records (that were ingested before the column was added to the table).

    in order to populate a calculated column at ingestion time, you can use an update policy.

    see: