title: update NULL value in SQlite
body: <p>I have a table with a few NULL values in an integer column and I set one of those values to 2.</p>
  
  <p>I have tested the statement by replacing those NULL values with numbers, and the statement updates the values correctly, however whenever I try to update a NULL value, it just stays NULL.</p>
  
  <p>in the context of this app, the value could be either NULL, 0 or 1, and at this point would run an UPDATE command to set the value to 2. it works for the 0s and 1s, and works if i replace null values with something else such as a 9, however it would be convenient to leave them as NULL- But it doesn't update as NULL!</p>
  
  <p>How would I go about fixing this?</p>