Powershell to execute SQL SCRIPTS - powershell

Question

anyone know how to rewrite below code, so it can invoke sql script. For instance, instead of put 'SELECT ##SERVERNAME AS ServerName' in the powershell script, I would like to put it into sql file.
$Path = "D:\AdminStuff\PowerShell\Password\Password.txt"
$uid = 'sa'
$pwd = Get-Content D:\AdminStuff\PowerShell\Password\Password.txt | ConvertTo-SecureString
$pwd.MakeReadOnly()
$creds = New-Object System.Data.SqlClient.SqlCredential($uid,$pwd)
$con = New-Object System.Data.SqlClient.SqlConnection
$con.ConnectionString = "Server=SLB-CLMFZ52;Database=master;"
$con.Credential = $creds
$con.Open()
$sql = "SELECT ##SERVERNAME AS ServerName"
$cmd = New-Object System.Data.SqlClient.SqlCommand($sql,$con)
$rdr = $cmd.ExecuteReader()
while($rdr.Read())
{
$rdr["ServerName"].ToString()
}
$con.Close()

Answer 1

While you can use the SqlCredential, SqlConnection, and SqlCommand .NET classes as you show in your question, there are simpler alternatives. It is a lot less work, for example, to use the Invoke-Sqlcmd cmdlet instead. Invoke-Sqlcmd is essentially the venerable sqlcmd utility with a PowerShell disguise. Thus, assuming your query was in a file myScript.sql, you can just run this--the InputFile parameter provides the means to store your SQL in a separate file as you requested:
$InvokeParams = #{
Server = 'SLB-CLMFZ52'
Database = 'Master'
Username = 'sa'
Password = 'xyz'
InputFile = 'myScript.sql'
}
Invoke-SqlCmd #InvokeParams
Now the obvious problem with that, though, is the password must be in plain text. (Of course, the password in the OP was in plain text in a file, as well. :-) Unfortunately Invoke-Sqlcmd does not work with PowerShell credential objects, which would have made it a lot more secure. The only reasonable workaround to get some security is to use Windows Authentication instead of SQL authentication. Then you could, for example, omit the username and password, and the query will be invoked with secure credentials:
$InvokeParams = #{
Server = 'SLB-CLMFZ52'
Database = 'Master'
InputFile = 'myScript.sql'
}
Invoke-SqlCmd #InvokeParams
To use the cmdlet just Import-Module sqlps. For the basics of Invoke-SqlCmd take a look at TechNet and for a more in-depth treatment, including the vagaries of sqlps, see part 1 of my Practical PowerShell for SQL Server Developers and DBAs article.

Answer 2

What about something simple like this:
$sql=get-content $filename