Merge multiple CSV into one without using Excel.Application - excel

Question

I created a PowerShell script that allows me to merge multiple .CSV into one .XLSX file.
It works well on my computer:
$path = "C:\Users\Francesco\Desktop\CSV\Results\*"
$csvs = Get-ChildItem $path -Include *.csv
$y = $csvs.Count
Write-Host "Detected the following CSV files: ($y)"
Write-Host " "$csvs.Name"`n"
$outputfilename = "Final Registry Results"
Write-Host Creating: $outputfilename
$excelapp = New-Object -ComObject Excel.Application
$excelapp.SheetsInNewWorkbook = $csvs.Count
$xlsx = $excelapp.Workbooks.Add()
for ($i=1;$i -le $y;$i++) {
$worksheet = $xlsx.Worksheets.Item($i)
$worksheet.Name = $csvs[$i-1].Name
$file = (Import-Csv $csvs[$i-1].FullName)
$file | ConvertTo-Csv -Delimiter "`t" -NoTypeInformation | clip
$worksheet.Cells.Item(1).PasteSpecial() | Out-Null
}
$output = "C:\Users\Francesco\Desktop\CSV\Results\Results.xlsx"
$xlsx.SaveAs($output)
$excelapp.Quit()
The problem is that I need to run this on several servers and servers are well known for not having Office installed so I cannot use Excel.Application.
Is there a way to merge multiple CSV into one CSV or XLSX without using Excel.Application and saving each CSV into a different sheet?

Answer 1

#AnsgarWiechers is right, ImportExcel is powerful and not difficult to use. However for your specific case you can use a more limited approach, using OleDb (or ODBC or ADO) to write to an Excel file like a database. Here is some sample code showing how to write to an Excel file using OleDb.
$provider = 'Microsoft.ACE.OLEDB.12.0'
$dataSource = 'C:\users\user\OleDb.xlsb'
$connStr = "Provider=$provider;Data Source=$dataSource;Extended Properties='Excel 12.0;HDR=YES'"
$objConn = [Data.OleDb.OleDbConnection]::new($connStr)
$objConn.Open()
$cmd = $objConn.CreateCommand()
$sheetName = 'Demo'
$cmd.CommandText = 'CREATE TABLE $sheetName (Name TEXT,Age NUMBER)'
$cmd.ExecuteNonQuery()
$cmd.CommandText = "INSERT INTO demo (Name,Age) VALUES ('Adam', 20)"
$cmd.ExecuteNonQuery()
$cmd.CommandText = "INSERT INTO demo (Name,Age) VALUES ('Bob',30)"
$cmd.ExecuteNonQuery()
$cmd.Dispose()
$objConn.Close()
$objConn.Dispose()
You didn't say much about the CSV files you'll be processing. If column data varies, to create the table you'll have to get the attribute (column) names from the CSV header (either by reading the first line of the CSV file, or by enumerating the properties of the first item returned by Import-CSV).
If your CSV files have a large number of lines, writing one line at a time may be slow. In that case using a DataSet and OleDbDataAdapter might improve performance (but I haven't tested). But at that point you might as well use OleDb to read the .csv directly into a DataSet, create a OleDbDataAdapter, set the adapter's InsertCommand property, and finally call the adapters Update method. I don't have time to write and test all that.
This is not intended as a full solution, just a demo of how to use OleDb to write to an Excel file.
Note: I tested this on a server that didn't have Office or Excel installed. The Office data providers pre-installed on that machine were 32-bit, but I was using 64-bit PowerShell. To get 64-bit drivers I installed the Microsoft Access Database Engine 2016 Redistributable and that's what I used for testing.

Answer 2

Time has passed and I have found a new solution: Install-Module -Name ImportExcel
This way the module takes care of the job like in this script.