I have two csv files. They both have SamAccountName in common. User records may or may not have a match found for every record between both files (THIS IS VERY IMPORTANT TO NOTE).

I am trying to basically just merge all columns (and their values) into one file (based from the SamAccountNames found in the first file...).

If the SamAccountName is not found in the 2nd file, it should add all null values for that user record in the merged file (since the record was found in the first file).

If the SamAccountName is found in the 2nd file, but not in the first, it should ignore merging that record.

Number of columns in each file may vary (5, 10, 2, so forth...).

Function MergeTwoCsvFiles
{
    Param ([String]$baseFile, [String]$fileToBeMerged, [String]$columnTitleLineInFileToBeMerged)
    
    $baseFileCsvContents = Import-Csv $baseFile
    $fileToBeMergedCsvContents = Import-Csv $fileToBeMerged
    
    $baseFileContents = Get-Content $baseFile
    
    $baseFileContents[0] += "," + $columnTitleLineInFileToBeMerged
    
    $baseFileCsvContents | ForEach-Object {
        $matchFound = $False
        $baseSameAccountName = $_.SamAccountName
        [String]$mergedLineInFile = $_
        
        [String]$lineMatchFound = $fileToBeMergedCsvContents | Where-Object {$_.SamAccountName -eq $baseSameAccountName}
        Write-Host '$mergedLineInFile =' $mergedLineInFile
        Write-Host '$lineMatchFound =' $lineMatchFound
        Exit
    }
}

The problem is, the record in the file is being written as a hash table instead of a string like line (if you were to view it as .txt). So I'm not really sure how to do this...

Adding results csv example files...

First CSV File

"SamAccountName","sn","GivenName"
"PBrain","Pinky","Brain"
"JSteward","John","Steward"
"JDoe","John","Doe"
"SDoo","Scooby","Doo"

Second CSV File

"SamAccountName","employeeNumber","userAccountControl","mail"
"KYasunori","678213","546","KYasunori@mystuff.com"
"JSteward","43518790","512","JSteward@mystuff.com"
"JKibogabi","24356","546","JKibogabi@mystuff.com"
"JDoe","902187u4","1114624","JDoe@mystuff.com"
"CStrife","54627","512","CStrife@mystuff.com"

Expected Merged CSV File

"SamAccountName","sn","GivenName","employeeNumber","userAccountControl","mail"
"PBrain","Pinky","Brain","","",""
"JSteward","John","Steward","43518790","512","JSteward@mystuff.com"
"JDoe","John","Doe","902187u4","1114624","JDoe@mystuff.com"
"SDoo","Scooby","Doo","","",""

Note: This will be part of a loop process in merging multiple files, so I would like to avoid hardcoding the title names (with $_.SamAccountName as an exception)

Trying suggestion from "restless 1987" (Not Working)

$baseFileCsvContents = Import-Csv 'D:\Scripts\Powershell\Tests\base.csv'
$fileToBeMergedCsvContents = Import-Csv 'D:\Scripts\Powershell\Tests\lookup.csv'
$resultsFile = 'D:\Scripts\Powershell\Tests\MergedResults.csv'
$resultsFileContents = @()

$baseFileContents = Get-Content 'D:\Scripts\Powershell\Tests\base.csv'

$recordsMatched = compare-object $baseFileCsvContents $fileToBeMergedCsvContents -Property SamAccountName

switch ($recordsMatched)
{
    '<=' {}
    '=>' {}
    '==' {$resultsFileContents += $_}
}

$resultsFileCsv = $resultsFileContents | ConvertTo-Csv
$resultsFileCsv | Export-Csv $resultsFile -NoTypeInformation -Force

Output gives a blank file :(