How to combine two lists into third list in SharePoint online programmatically?

Question

I have two lists in SharePoint Online:

1. List1["https://siteName.sharepoint.com/sites/Test1"] (Importing items form excel)
   Fields: Name,Contact,Email
2. List2["https://siteName.sharepoint.com/"]
   Fields: Name,Contact,Email
3. List3["https://siteName.sharepoint.com/sites/Test3"]
   Fields: Name,Contact,Email

List1 and List2 have list-items and List3 has only fields My requirement is that I want to merge List1 and List2 in List3.

For example, In List1 - 10 items and in List2 - 30 items then I need 40 items in List3

How can i achieve this?

Thanks in advance.

Answer 1

You can get a list of all of the items and write them to a csv using the script below. Make sure to replace the site name, list name, and fieldvalues.columnName before running.

Connect-PnPOnline "https://tenant.sharepoint.com/site1"
$csv = "path/to.csv"
$List1 = Get-PnPList -Identity "List1Name"
$items = Get-PnPListItem -List $List1
foreach ($item in $items) {
    $item.FieldValues
    $newRow = "{0},{2},{3}" -f $item.FieldValues.name, $item.FieldValues.Contact, $item.FieldValues.Email
    $newRow | Add-Content -path $csv
}

You can repeat the same script for the second list to create a csv with all of the items from lists 1 and 2. Once that is complete, you can then use the below to add all of the items in the csv to list3.

Connect-PnPOnline "https://tenant.sharepoint.com/site2"
$list3 = Get-PnPList -Identity "List3"

foreach ($row in $csv) {
    Add-PnPListItem -List $list3 -Values @{"Name" = $row.name; "Contact" = $row.Contact; "Email" = $row.Email}
}