Powershell / SQL Server / Import-CSV - sql-server

Question

Working on another script for work and I'm attempting to read from a CSV containing only one column of data. And then for each item to find the corresponding ID when querying the SQL database. Then to put the result(ID1, CSVID1) in to an excel file(I have this part working fine).
Now I have run in to an issue as to how to populate the dataset within a foreach loop.
$excelAssets = Import-Csv .\test.csv -Header assetId | Foreach-Object {
$assetId = $_.assetId
# SQL Query Variables
$query = "SELECT AssetId AS AssetID, BrandId AS BrandID FROM [AssetLibrary_BrandAsset] WHERE AssetId = $assetId"
$connection = New-SqlConnection -Server $dataSource -Database $dataBase
#Execute the SQL commands and place the results in dataset
if ($connection.State -eq 'Open')
{
$swLap = Start-Elapsed $sw "Executing SQL Query"
Write-Verbose "$query";
$dataSet += Invoke-SQLQuery -connection $connection -query $query -ExecutionTimeout '0'
$i++
$connection.Close();
End-Elapsed $sw $swLap
} ELSE {
Write-Error "$($(Format-Elapsed $swLap)) SQL Connection Not Open - Exiting...";
exit;
}
}
Now $dataSet += doesn't work and I have googled numerous times to try and find the answer to this problem. Any help is appreciated.
Using the $dataSet
$dataTable = new-object "System.Data.DataTable" "Results"
$dataTable = $dataSet.Tables[0]
$rowDT = $dataTable.Rows.Count;
$colDT = $dataTable.Columns.Count;
Write-Host -NoNewLine "$(Format-Elapsed $sw.Elapsed) Rows: ";
Write-Host -NoNewLine "$($rowDT+1)" -ForegroundColor "Green";
Write-Host -NoNewLine " Columns: "
Write-Host -NoNewLine "$($colDT+1)" -ForegroundColor "Green";
Write-Host -NoNewLine " Cells: "
Write-Host "$( ($colDT+1)*($rowDT+1) )" -ForegroundColor "Green";
#Create a 2D Array of the DataTable
# http://stackoverflow.com/questions/13184191/fastest-way-to-drop-a-dataset-into-a-worksheet
$tableArray = New-Object 'object[,]' $rowDT, $colDT;
$swLap = Start-Elapsed $sw "DataTable transformation"
# i = row and j = column
for ($i=0;$i -lt $rowDT; $i++)
{
#Write-Progress -Activity "Transforming DataTable" -status "Row $i" -percentComplete ($i / $rowDT*100)
for ($j=0;$j -lt $colDT; $j++)
{
$tableArray[$i,$j] = $dataTable.Rows[$i].Item($j).ToString();
}
}
End-Elapsed $sw $swLap
$rowOffset = 1; $colOffset = 1;# 1,1 = "A1"
# Write out the header column names
for ($j=0;$j -lt $colDT; $j++)
{
$ActiveWorksheet.cells.item($rowOffset, $j+1) = $dataTable.Columns[$j].ColumnName;
}
$headerRange = $ActiveWorksheet.Range($ActiveWorksheet.cells.item($rowOffset, $colOffset), $ActiveWorksheet.cells.item($rowOffset, $colDT+$colOffset-1));
$headerRange.Font.Bold = $false
$headerRange.Interior.Color = $headingColour
$headerRange.Font.Name = $headingFont
$headerRange.Font.Color = $headingFontColour
$rowOffset++;
# Extract the data to Excel
$tableRange = $ActiveWorksheet.Range($ActiveWorksheet.cells.item($rowOffset, $colOffset), $ActiveWorksheet.cells.item($rowDT+$rowOffset-1, $colDT+$colOffset-1));
$tableRange.Cells.Value2 = $tableArray;
# Resize the columns in Excel
$swLap = Start-Elapsed $sw "Resize Excel Worksheet"
$wholeRange = $ActiveWorksheet.UsedRange
$wholeRange.EntireColumn.AutoFit() | Out-Null
End-Elapsed $sw $swLap
# Save Excel workbook
$ActiveWorkbook.SaveAs("$OutputFile")
$ActiveWorkbook.Close()

Answer 1

After assigning to $dataSet the first time, it's type is probably not array, meaning that the += operator doesn't behave exactly as you expect.
You can either initialize $dataSet as an empty array before you start assigning to it:
Import-Csv .\test.csv -Header assetId | Foreach-Object -Begin {$dataSet = #()} -Process {
# rest of script in here
} -End {return $dataSet}
or you can cast it during assigning:
[array]$dataSet += Invoke-SQLQuery -connection $connection -query $query -ExecutionTimeout '0'
finally, an alternative solution would be to ensure that the output from Invoke-SQLQuery is treated as an array before you assign it to $dataSet:
$dataSet += #(Invoke-SQLQuery -connection $connection -query $query -ExecutionTimeout '0')
Whatever suits your style of coding.