title: Kusto | Azure Data Explorer | extractjson() returns nothing
body: <p>I am trying to use the extractjson() function in Kusto/Azure Data Explorer. I read in the MS documentation that when you need to extract more than one element of a JSON compound object it's better to use parse_json(), but in my scenario I just need to extract one value from the JSON, so I'm assuming that conversely it would be best to use extractjson(). Here is a sample table to illustrate:</p>
  <pre><code>let T = datatable (myObject:string)[
      '[{&quot;Id&quot;:1,&quot;Value&quot;:&quot;light saber&quot;}]',
      '[{&quot;Id&quot;:2,&quot;Value&quot;:&quot;jedi beacon&quot;}]'
  ];
  T
  | extend JediTools = extractjson(&quot;$.Value&quot;, myObject)
  </code></pre>
  <p>On the last line I am attempting to extend a column to contain the extracted json values, but instead I get nothing:
  <a href="https://i.stack.imgur.com/P2lcg.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/P2lcg.png" alt="actual output from extractjson() function" /></a></p>
  <p>Expected results:</p>
  <p><a href="https://i.stack.imgur.com/igJ9Z.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/igJ9Z.png" alt="expected output from extractjson() function" /></a></p>
  <p>The function must be finding &quot;Value&quot; because it's not throwing an error, but <strong>why is the column blank where it should show the extracted values?</strong> I also tried the following but the result is the same:</p>
  <p><code>| extend JediTools = extractjson(&quot;$.Value&quot;, myObject, typeof(string))</code></p>
  <p><code>| extend JediTools = tostring(extractjson(&quot;$.Value&quot;, myObject))</code></p>