Need to filter a dataset

I have a dataset that I get the unique values of an OrderID from. Then I need to get the set of items from each OrderID. The output of my code is returning the unique OrderID list instead of the set.

$orderIdList = $packageItems.Tables.Rows.Orderid | Sort-Object | Get-Unique

foreach ($item in $orderIdList) {

    $itemGroup = $orderIdList | Where-Object {$orderIdList -contains $item}

$orderIdList is just a list of unique order IDs - that’s what your first command is doing.

$itemGroup = $orderIdList | Where-Object {$orderIdList -contains $item}

Presumably, $orderIdList in the above statement should refer to something else?

Think you should take a look at Group-Object:

$grpOrders = $packageItems.Tables.Rows | Group-Object -Property OrderId

Here is a basic example:

$orders = @"
4567,,Shoes 10.5
4570,,Shirt XL
4567,,Shirt XL
4561,,Pants Small
4567,,Pant XL
"@ | ConvertFrom-Csv

$grpOrders = $orders | Group-Object -Property OrderId

foreach ($order in $grpOrders) {
    'Processing order {0} with {1} items' -f $order.Name, $order.Count 
    foreach ($orderItem in $order.Group) {
        'Processing item {0}' -f $orderItem.Item


PS C:\Users\rasim> $grpOrders

Count Name                      Group
----- ----                      -----
    1 4561                      {@{OrderId=4561;; Item=Pants Small}}
    3 4567                      {@{OrderId=4567;; Item=Shoes 10.5}, @{OrderId=4567;; Item=Shirt XL}, @{OrderId=4… 
    1 4570                      {@{OrderId=4570;; Item=Shirt XL}}

PS C:\Users\rasim> c:\Users\rasim\Desktop\temp.ps1
Processing order 4561 with 1 items
Processing item Pants Small
Processing order 4567 with 3 items
Processing item Shoes 10.5
Processing item Shirt XL
Processing item Pant XL
Processing order 4570 with 1 items
Processing item Shirt XL
1 Like

Yes, my bad, I got mixed up when modifying the code to post. I was using $packageItems.Tables.Rows.Orderid but it still returns all records instead of the $item value.

Thank you rob-simmers, that is a very elegant solution!