> For the complete documentation index, see [llms.txt](https://sandyzeng.gitbook.io/kql/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://sandyzeng.gitbook.io/kql/kql-quick-guide/need-to-practice-more/set_difference.md).

# set\_difference

```
let RequiredApps = toscalar (datatable (AppName: string) [
 "1Password",
 "Camtasia 2021",
 "Azure Monitor Agent"
]
| summarize  make_set(AppName));
AppInventory_CL
| where TimeGenerated > ago (7d)
| summarize arg_max(TimeGenerated, *) by ManagedDeviceID_g, AppName_s
| summarize  InstalledApps = make_set(AppName_s) by ManagedDeviceID_g, ComputerName_s
| extend  MissingApps= set_difference(RequiredApps, InstalledApps)
| where MissingApps <> '[]'
| project ComputerName_s, MissingApps
```

<figure><img src="/files/L0C4ooLXRetVzK0KT7e9" alt=""><figcaption></figcaption></figure>