(for-each-row scenario).in kusto - azure-data-explorer

Question

Query1
cluster(x).database('$systemdb').Operations
| where Operation == "DatabaseCreate" and Database contains "oci-"| where State =='Completed'
and StartedOn between (datetime(2020-04-07) .. 3d)
| distinct Database , StartedOn
| order by StartedOn desc
Output of my query1 is list of databases , now I have to pass each db value into query2 to get buildnumber
Query2:
set query_take_max_records=5000;
let view=datatable(Property:string,Value:dynamic)[];
let viewFile=datatable(FileName:string)[];
alias database db = cluster(x).database('y');
let latestInfoFile = toscalar((
union isfuzzy=true viewFile,database('db').['TextFileLogs']
| where FileName contains "AzureStackStampInformation"
| distinct FileName
| order by FileName
| take 1));
union isfuzzy=true view,(
database('db').['TextFileLogs']
| where FileName == latestInfoFile
| distinct LineNumber,FileLineContent
| order by LineNumber asc
| summarize StampInfo=(toobject(strcat_array(makelist(FileLineContent,100000), "\r\n")))
| mvexpand bagexpansion=array StampInfo
| project Property=tostring(StampInfo[0]), Value=StampInfo[1]
)|where Property contains "StampVersion" | project BuildNumber = Value;

Answer 1

database() function: is a special scoping function, and it does not support non-constant arguments due to security consideration.
As a result - you cannot use sub-query to fetch list of databases and then operate on this list as input for database() function.
This behavior is described at:
https://learn.microsoft.com/en-us/azure/kusto/query/databasefunction?pivots=azuredataexplorer
Syntax
database(stringConstant)
Arguments
stringConstant: Name of the database that is referenced. Database identified can be either DatabaseName or PrettyName. Argument has to be constant prior of query execution, i.e. cannot come from sub-query evaluation.