title: Modify database value if a different vaule matches a CSV file
body: <p>Ok, I am new here and if my question has already been answered, please direct me, but I cannot find it.</p>
  
  <p>I have a database with products in it. I receive a list of product codes from my supplier in a csv format. It has only 1 column. I want to take that list of product codes and compare to the list of codes in my database. If a product code is on the list in the csv, I want to modify a stock status value for that product in the database. so basically,</p>
  
  <p>if "item_a" exists, change "value_b".</p>
  
  <p>I hope I have been clear enough to get the correct answer...</p>
  
  <p>Thank you in advance.</p>
  
  <p>P.S. This>><a href="https://stackoverflow.com/questions/9872551/php-mysql-import-csv-and-then-compare-and-remove-redundant-entries">PHP MYSQL import CSV and then compare and remove redundant entries</a>
  seems to be in the right direction, however instead of deleting, I  want to change a different value</p>