title: select fields by using a list in another excel file
body: <p>I work with a CRM to send mailings to contacts. I want to update my unsubscribers so they won't receive any emails anymore.</p>
  
  <p>I cant really make a query of it so I just have a list of people who want to unsubscribe. The list is too big to modify it manually. </p>
  
  <p>Do you guys have any idea how I can approach this problem? </p>
  
  <p>I was thinking exporting the full database to Excel and apply some kind of function where I can select the list I have all at once and change the boolean field (receive emails) to NO.</p>