Help! Custom properties and piping

Hi Guys,

Pretty new to powershell here and was just learning it using the Morelunches book on Powershell and came upon one of the labs in chapter 9 that got me a bit confused. The commands are supposed to filter out computers on the domain and retrieve all hot-fixes on them. In the lab, it says that the follow command lines are supposed to be equivalent but when I run the second string, it only reports the hotfixes on the local machine… Can anyone shed some light on why this is?

First command:

Get-Hotfix -computerName (get-adcomputer -filter * | Select-Object -expand name)

Second command:

get-adcomputer -filter * | Select-Object @{l='computername';e={$_.name}} | Get-Hotfix

Thanks in advance for all your help!!
Leonard