title: Turning multiple rows into single row based on ID, and keeping null values
body: <p>I have tried some of the various solutions posted on Stack for this issue but none of them keep null values (and it seems like the entire query is built off that assumption). </p>
  
  <p>I have a table with 1 million rows.  There are 10 columns. The first column is the id.  Each id is unique to "item" (in my case a sales order) but has multiple rows.  Each row is either completely null or has a single value in one of the columns.  No two rows with the same ID have data for the same column.  I need to merge these multiple rows into a single row based on the ID. However, I need to keep the null values. If the first column is null in all rows I need to keep that in the final data. </p>
  
  <p>Can someone please help me with this query I've been stuck on it for 2 hours now.  </p>
  
  <pre class="lang-none prettyprint-override"><code>id - Age - firstname - lastname
  1    13      null      null
  1    null     chris    null
  </code></pre>
  
  <p>should output</p>
  
  <pre class="lang-none prettyprint-override"><code>1 13 chris null
  </code></pre>