title: Import Data into MySQL table from CSV file without Overwriting Existing Data
body: <p>I have a csv file with data that I want to import into a table.  Some of the data already exists in the table and I don't want to add a duplicate row.</p>
  
  <p>For example, I have apple in a row in the table, and apple in a row in the CSV file with additional information.</p>
  
  <p>I don't want a new row added to the table or to overwrite any of the data in the existing row; just add the additional data for that row from the CSV file into the table row.</p>
  
  <p>How can I avoid a duplicate row being added or overwriting data, or do I even have to worry about this.</p>