When a word matches retrieve the varying string after it - powershell

Question

I have a query which looks like this:
FROM TableA
INNER JOIN TableB
ON TableA.xx = TableB.xx
INNER JOIN TableC
ON TableA.yy = TableC.yy
I am trying to write a script which selects the tables which come after the word "JOIN".
The script that I wrote now is:
$data = Get-Content -Path query1.txt
$dataconv = "$data".ToLower() -replace '\s+', ' '
$join = 0
$overigetabellen = ($dataconv) | foreach {
if ($_ -match "join (.*)") {
$join++
$join = $matches[1].Split(" ")[0]
#Write-Host "Table(s) on which is joined:" $join"."
$join
}
}
$overigetabellen
This gives me only the first table, so TableB.
Can anyone help me how I get the second table also as output?

Answer 1

Process your data with Select-String:
$data | Select-String -AllMatches -Pattern '(?<=join\s+)\S+' |
Select-Object -Expand Matches |
Select-Object -Expand Groups |
Select-Object -Expand Value
(?<=...) is a so-called positive lookbehind assertion that is used for matching the pattern without being included in the returned string (meaning the returned matches are just the table names without the JOIN before them).

Answer 2

This is my naive attempt to find the desired table names.
Split the data input on whitespace into an array, find the indices of the word "JOIN", and then access the following indices after the word "JOIN."
$data = Get-Content -Path query1.txt
$indices = #()
$output = #()
$dataarray = $data -split '\s+'
$singleIndex = -1
Do{
$singleIndex = [array]::IndexOf($dataarray,"JOIN",$singleIndex + 1)
If($singleIndex -ge 0){$indices += $singleIndex}
}While($singleIndex -ge 0)
foreach ($index in $indices) {
$output += $dataarray[$index + 1]
}
Outputs:
TableB
TableC
You can adjust for capitalization (saw you set your input to all lowercase), etc as needed if you expect varying input files.