SQL ExecuteReader throws "Incorrect syntax near GO" - sql-server

Question

I use a T-SQL command which I found here to get the fragmentation of my database tables. When I execute the T-SQL in the Management Studio, everything works. If I use it inside PowerShell, I get the following error (translated from German):
Exception when calling "ExecuteReader" with 0 Argument(s):
"Incorrect syntax near 'GO'.
Incorrect syntax near 'GO'."
In Zeile:17 Zeichen:6
+ $Result = $cmd.ExecuteReader()
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : NotSpecified: (:) [], MethodInvocationException
+ FullyQualifiedErrorId : SqlException
This is the part of my script which throws the error
foreach ($table in $tables)
{
$Data = New-Object System.Data.DataTable
$cmd = New-Object System.Data.SqlClient.SqlCommand
$getFragRate = "
-- SQL Command von Microsoft um die Index Fragmentation zu überprüfen
USE Logik;
GO
SELECT a.index_id, name, avg_fragmentation_in_percent
FROM sys.dm_db_index_physical_stats (DB_ID(N'Logik'), OBJECT_ID(N'$($table)'), NULL, NULL, NULL) AS a
JOIN sys.indexes AS b ON a.object_id = b.object_id AND a.index_id = b.index_id;
GO
"
$cmd.CommandText = $getFragRate
$cmd.Connection = $con
$Result = $cmd.ExecuteReader()
$Data.Load($Result)
$Data
}
Why does this error occur?
The User I use to do this has sysadmin, db_ddladmin and db_owner permission.
Edit: Another T-SQL Command to get all tables of my database worked without a problem from PowerShell.

Answer 1

GO is NOT a T-SQL command - therefore you cannot have it in T-SQL statements being executed from PowerShell.
GO is a batch separator used by SQL Server Management Studio.
You need to break up that statement into several individual statements yourself and execute them one by one.