Metadata keywords

Question

I use Bridge to append Metadata to the Keywords field. I would like the  script below to get a a total file count of the PDFs containing ONLY the keyword "correction" on selected folders & output that info to a text file.
I'm having difficulties  with mdfind & mdls. I have no knowledge on Terminal commands. Let's say I have a 4 folders with 200 pdfs each some of them have the keyword "correction"  I want the final result on the text file be:
folder 1 CORRECTS= 50  
folder 2 CORRECTS= 58 
folder 3 CORRECTS= 115  
folder 4 CORRECTS= 35
I'm just need the correct syntax code to make this work
set target_folder to choose folder with prompt "Choose target folders" with multiple selections allowed without invisibles
set results to ""
repeat with i from 1 to (count target_folder)
  set thisFolder to (POSIX path of item i of target_folder)
  --->>>> THIS iS THE PART I NEED HELP WITH -----<<<<
  set fileCount to paragraphs of (do shell script "mdfind '  kMDItemKeywords == correction' -count") & quoted form of thisFolder
¬--& " -type f  -iname *.pdf | wc -l"
  set results to (results & "" & tab & "CORRECTS=" & tab & fileCount & return)
  --->>>> THIS iS THE PART I NEED HELP WITH -----<<<<
end repeat
set theFilePath to (path to desktop folder as string) & "PDF correction count.txt"
set theFile to open for access file theFilePath with write permission
try
  set eof of theFile to 0
  --write results to file theFilePath
  write results to theFile
  close access theFile
on error
  close access theFile
end try

Answer 1

I have three PDF documents on my Desktop that each have a correction keyword in them. The following syntax will restrict the mdfind to looking only in that Desktop folder, and find the case-insensitive word "correction."
If you use wc -l after the mdfind, you will get a multiple left space padded text item. By using the count of paragraphs, this results in a a nice neat integer value.
set thisFolder to POSIX path of ((path to desktop) as text)
set results to ""
set fileCount to count of paragraphs of (do shell script ¬
      "mdfind -onlyin " & quoted form of thisFolder ¬
      & " -name 'kMDItemKeywords == \"correction\"cdw' *.pdf")
log fileCount
-- result: 3
set results to results & name of (info for thisFolder) & space & "CORRECTS= " & fileCount & return
-- result: Desktop CORRECTS= 3