title: ADF Data Flow flatten JSON to rows
body: <p>IN ADF Data Flow how can I flatten JSON into rows rather than columns?</p>
  <pre><code>{                   
                  &quot;header&quot;: [
                      {                           
                          &quot;main&quot;: {                                
                              &quot;id&quot;: 1                               
                          },
                          &quot;sub&quot;: [
                              {
                                  &quot;type&quot;: &quot;a&quot;,                                   
                                  &quot;id&quot;: 2                                  
                              },
                              {
                                  &quot;type&quot;: &quot;b&quot;,                                   
                                  &quot;id&quot;: 3                                 
                              }
                                
                                ]}]}
  </code></pre>
  <p>In ADF I'm using the flatten task and get the below result:</p>
  <p><a href="https://i.stack.imgur.com/S8mrY.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/S8mrY.png" alt="enter image description here" /></a></p>
  <p>However the result I'm trying to achieve is merging the two id columns into one column like below:</p>
  <p><a href="https://i.stack.imgur.com/DcIPf.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/DcIPf.png" alt="enter image description here" /></a></p>