Let us discuss how to access Look up values information about lists via PowerShell. In the SharePoint hierarchy, In laymen terms ,it is a referential integrity between the lists in SharePoint. We will create lookup columns, when we need to create relationship between two lists.
To create a relationship between two lists, in the source list, you create a lookup column that retrieves one or more values from a destination list.
In this blog, I have given the piece of code to retrieve the sharepoint look up columns.
spweb = Get-SPWeb "http://mysite
$list = $spweb.Lists["MyPortalList"]
$query = New-Object Microsoft.SharePoint.SPQuery
$query.query ="<Where><Eq><FieldRef Name='Type'/><Value Type='Lookup'>Technologies</Value></Eq></Whre>"
$items = $list.getItems($query)
$items | Format-Table -Property ID, Title, @{Label="Type";Expression={(new-object Microsoft.SharePoint.SPFieldLookupValue($_["Type"])).LookupValue}}
$spweb.Dispose()
Happy SharePointing :-)