Querying SQL db based off of values in a CSV and exporting filtered list to a new CSV

Question

Hello, we use Office365 for our student e-mail accounts and are trying to appropriately license those accounts based on if they are currently enrolled or not (currently enrolled get the full license with OneDrive, SharePoint, Lync, Office download etc. while
non-currently enrolled get e-mail only).  I have exported a list of UserPrincipalNames from Office365 to a CSV that have a particular license applied.  I want to compare that list against a SQL view that will identify if those UserPrincipalNames
(found under the "Email" column in the SQL database) are currently registered for classes or not (we have a "CurrentlyRegistered" column populated with a "0" for not registered and a "1" for registered"). 
I then need to export the filtered list of UserPrincipalNames to a different CSV so that I can use that second CSV to change the license in Office365.
For example, I export a list of accounts from Office 365 that have the e-mail only license applied to a CSV named "Exchange.csv" that has a single column of data with a header of "UserPrincipalName".  I want to compare the accounts
in the "Exchange.csv" to our SQL view (which among other columns, has one named "Email" that matches the values of "UserPrincipalName" and a "CurrentlyRegistered" column) to see if any have changed status to being currently
enrolled so that I can flip their license to the full license. I would know this by returning any accounts that have a "1" in the "CurrentlyRegistered" column and saving those to a CSV named "Full.csv" that would have two columns
with headers "Email" and "CurrentlyRegistered".
I need to know how to connect to SQL from PowerShell and return the filtered list of accounts that have changed status.  I am hoping for something like:
$constring = "Server=MyServer\Instance;Database=StudentEmails;Trusted_Connection=True"
$SqlConnection = New-Object System.Data.SqlClient.SqlConnection
$SqlConnection.ConnectionString = $constring
$SqlCommand = New-Object System.Data.SqlClient.SqlCommand
$SqlCommand.CommandText = $query
$SqlCommand.Connection = $SqlConnection
$SqlAdapter = New-Object System.Data.SqlClient.SqlDataAdapter
$SqlAdapter.SelectCommand = $SqlCommand
$DataSet = New-Object System.Data.DataSet
$SqlConnection.Open()
$SqlAdapter.Fill($DataSet)
$SqlConnection.Close()
$DataSet.Tables[0]
Remove-Item C:\O365Operations\CSVs\Full.csv
$query = Import-Csv C:\O365Operations\CSVs\Exchange.csv | ForEach-Object {Invoke-Sqlcmd -Query "SELECT [Email],[CurrentlyRegistered] FROM [StudentEmails].[dbo].[v_StudentEmailAccounts] WHERE CurrentlyRegistered = '1'"} | Export-Csv C:\O365Operations\CSVs\Full.csv
-Append}
Am I anywhere close with this?
Thanks,
Jeremy Hawks
Systems Administrator @ Green River College

Answer 1

My CSV has a single column with a the #Type in the first line, the header of "UserPrincipalName" in the second line and the rest of the lines having a single e-mail address, similar to:
#TYPE Selected.Microsoft.Online.Administration.User
UserPrincipalName
[email protected]
[email protected]
[email protected]
The "Email" column in SQL will have some matching values to the "UserPrincipalName" column in the CSV. 
So if any of the (UserPrincipalName in CSV) values match the values found in the column (Email in SQL) then I want to export those e-mail addresses to a CSV so that I can use the new CSV to change the licenses in Office 365.
When I run your modified code I get the following:
PS C:\Windows\system32> $csv=Import-Csv C:\O365Operations\CSVs\Test.csv
$csv|select email
foreach($User in $csv){
     # find user
     if($DataTable|?{$_.Email -eq $user.Email}){
         Write-Host "User found: $($user.email)" -fore green
         #Select Email,CurrentlyRegistered | Export-Csv C:\O365Operations\CSVs\IW2.csv -Append
     }else{
        Write-Host "User NOT found: $($user.email)" -fore red
email
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
User NOT found:
PS C:\Windows\system32>
If I change the command from
$csv|select email
to
$csv|select UserPrincipalName
Then I get a full listing of the e-mails in the CSV with none filtered out (so it is not comparing it to the returned data from the SQL table.
Suggestions?
Jeremy Hawks Systems Administrator @ GRC