title: Replacing missing values in sqlite tables
body: <p>I have a table which I created in sqlite that looks like this:</p>
  
  <pre><code>  Age   Height
     12     186
            175
            169
     13
     15     171
  </code></pre>
  
  <p>I want to replace the missing values in each column with its column mean. I have used the update  function but there does not seem to be any visible update in the table. Say the table above is called test, I did this already</p>
  
  <pre><code>UPDATE test SET Age=13.3 WHERE Age IS NULL;
  
  UPDATE test SET Height=175.25 WHERE Height IS NULL;
  </code></pre>
  
  <p>Also, I would like to know how I can incorporate the mean automatically with a select statement without having to manually input it</p>