Powershell, invoke-sqlcmd, export-csv fails to show data if there is more than one result - sql

Question

I have the below code to get data from a SQL DB and export it into a CSV file:
#Server and Database names
$SQLServer = "Servername"
$DB = "DatabaseName"
#SQL Command
$FullScriptSQL="Select * from MyTable WHERE Column = 'TestData'"
#Invoke the command, rename the column headers and export to CSV file
$FullScriptCallLinked = Invoke-Sqlcmd -ServerInstance $SQLServer -Database $DB -Query $FullScriptSQL | select-object #{ expression={$_.Column1};label='Column1 Name'},#{ expression={$_.Column2};label='Column2 Name'},#{ expression={$_.Column3}; label='Column3 Name' },#{ expression={$_.Column4} ; label='Column4 Name' }
Export-CSV -Path ".\ResultFile\FullScript.csv" -inputobject $FullScriptCallLinked -Append -NoTypeInformation
This works perfectly if there is one result. But if there is more than one result, it will show the below in the csv file
I am at my wits end as to why it is doing this. It's obviously the DB parameter data or something to that effect. Been googling for a few days with no luck. Anyone smarter than I able to assist please?

Answer 1

Instead of using Select-Object to rename your columns, which is quite inefficient, you could give the alias to your columns on the query itself:
$SQLServer = "Servername"
$DB = "DatabaseName"
$query = #'
SELECT Column1 AS "Column1 Name",
Column2 AS "Column2 Name",
Column3 AS "Column3 Name",
Column4 AS "Column4 Name"
FROM MyTable
WHERE ColumnX = 'TestData'
'#
Invoke-Sqlcmd -ServerInstance $SQLServer -Database $DB -Query $query |
Export-CSV -Path ".\ResultFile\FullScript.csv" -NoTypeInformation
Also, as in my comment, the code you have on your question is fine and should work, the only problem was using -InputObject instead of piping the results to Export-Csv:
$FullScriptCallLinked | Export-Csv -Path ".\ResultFile\FullScript.csv" -NoTypeInformation

Answer 2

Figured it out. I knew I was close!
#Server and Database names
$SQLServer = "Servername"
$DB = "DatabaseName"
#SQL Command
$FullScriptSQL="Select * from MyTable WHERE Column = 'TestData'"
#Invoke the command, rename the column headers and export to CSV file
$FullScriptCallLinked = Invoke-Sqlcmd -ServerInstance $SQLServer -Database $DB -Query $FullScriptSQL
foreach($i in $FullScriptCallLinked){
select-object #{ expression={$_.Column1};label='Column1 Name'},#{ expression={$_.Column2};label='Column2 Name'},#{ expression={$_.Column3}; label='Column3 Name' },#{ expression={$_.Column4} ; label='Column4 Name' }
Export-CSV -Path ".\ResultFile\FullScript.csv" -inputobject $i -Append -NoTypeInformation
}