Updating and Deleting Data

• The UPDATE query lets you update columns of all records that fulfill a certain condition
• To add one to the quantity of every item in invoice number 11731

  UPDATE Item
     SET Quantity = Quantity + 1
     WHERE Invoice_Number = '11731'

• Update multiple column values by specifying multiple update expressions
  in the SET clause, separated by commas
• Both UPDATE and DELETE return the number of rows updated or deleted