How to join the 3 KQL tables?

Hi all,

I want to get the inactive users data with seesionhostname, hostpoolname, lastlogindate,username

and i am trying to get it through KQL query which we need to join 3 tables

i am getting the below error

'join' operator: Failed to resolve column named '_ResourceId' Request id: 1f89431c-0f50-44cb-ba4d-48fc0010d07c

 while running the below queires

let RecentConnections =      WVDConnections     | where TimeGenerated > ago(30d)  // Replace with your parameter     | summarize lastLogin=max(TimeGenerated) by UserName, _ResourceId;

let InactiveUsers =      RecentConnections     | where lastLogin < ago(7d)  // Replace with your parameter     | project UserName, lastLogin, _ResourceId;

let InactiveComputers =      WVDHeartbeat     | where TimeGenerated > ago(30d)  // Replace with your parameter     | summarize LastActive = max(TimeGenerated) by Computer     | where LastActive < ago(7d)  // Replace with your parameter     | project LastActive, Computer;

// Combine inactive users with their last active computers InactiveUsers     | join kind=inner (InactiveComputers) on InactiveUsers._ResourceId == InactiveComputers.Computer     | project UserName, lastLogin, LastActive, _ResourceId;

please let me know how can i resolve it

it should have generate all details with 100% accuracy & should also work in log analytics workspace

Thanks in Advance