sp_msforeachdb in dataset - powershell

Question

Can someone tell me why the following code only returns one row from the DataSet (for the master db) instead of one for each database on the server?
$SQLConn = New-Object System.data.SqlClient.SqlConnection
$SQLConn.ConnectionString = "Data Source = $SQLServer; Initial Catalog = master;
Integrated Security = True"
$SQLConn.Open()
$query = "exec sp_msForEachDb 'use [?] SELECT TOP 1 [name] FROM sysusers'"
$SQLCmd = New-Object System.Data.Sqlclient.SqlCommand($query, $SQLConn);
$SQLAdapter = New-Object System.Data.SqlClient.SqlDataAdapter
$SQLAdapter.SelectCommand = $SQLCmd
$DataSet = New-Object System.Data.Dataset
$SQLAdapter.Fill($DataSet) | out-null
ForEach ($row in $DataSet.Tables[0])
{
$Name = $row["name"]
write-host $Name
}
$SQLConn.Close()

Answer 1

Your code shows your using the index position 0 of $dataset.tables. Change it to $DataSet.Tables
ForEach ($row in $DataSet.Tables[0])
{
$Name = $row["name"]
write-host $Name
}
Change to...
ForEach ($row in $DataSet.Tables)
{
$Name = $row["name"]
write-host $Name
}

Answer 2

You're returning getting multiple datatables in your result set, but only showing the first one Tables[0]. Try this:
$DataSet.Tables | foreach {$_.name}
Here's some completed and tested code to combine result set:
$SQLServer = ".\SQL1"
$query = #"
create table #output
(DB varchar(128),
name varchar(128)
)
exec sp_MSforeachdb #command1='USE [?];
insert #output SELECT TOP 1 ''?'' AS ''DB'', [name]
FROM sysusers';
select * from #output
"#
$SQLConn = New-Object System.data.SqlClient.SqlConnection
$SQLConn.ConnectionString = "Data Source = $SQLServer; Initial Catalog = master;
Integrated Security = True"
$SQLConn.Open()
$SQLCmd = New-Object System.Data.Sqlclient.SqlCommand($query, $SQLConn);
$SQLAdapter = New-Object System.Data.SqlClient.SqlDataAdapter
$SQLAdapter.SelectCommand = $SQLCmd
$DataSet = New-Object System.Data.Dataset
$SQLAdapter.Fill($DataSet) | out-null
$DataSet.Tables[0]
$SQLConn.Close()

Answer 3

I think I needed to do something like this to get all of the records into one dataset:
$query = "DECLARE #users TABLE ([name] varchar(100)) INSERT #db_roles
exec sp_msForEachDB 'USE [?] SELECT [name] FROM sysusers'
SELECT [name] FROM #db_roles"