title: How to copy a partitioned table to another partitioned table in BigQuery
body: <p>I'm trying to copy one partitioned table into another one. According to the <a href="https://cloud.google.com/bigquery/docs/partitioned-tables#copying_partitioned_tables" rel="nofollow noreferrer">docs</a>, this should be possible.</p>
  
  <blockquote>
    <p>If you want to copy a partitioned table into another partitioned table, the partition specifications for the source and destination tables must match.</p>
  </blockquote>
  
  <p>To test, I created two partitioned tables (<code>partition1</code> &amp; <code>partition2</code>) with the same schema. I pushed 3 records into partition <code>$20170101</code> on the <code>partition1</code> table:</p>
  
  <pre><code>echo '{"a":1, "b":2}' | bq insert '&lt;removed&gt;.partition1$20170101'
  echo '{"a":1, "b":2}' | bq insert '&lt;removed&gt;.partition1$20170101'
  echo '{"a":1, "b":2}' | bq insert '&lt;removed&gt;.partition1$20170101'
  </code></pre>
  
  <p>That looks good:</p>
  
  <p><a href="https://i.stack.imgur.com/Xmlqd.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Xmlqd.png" alt="enter image description here"></a></p>
  
  <p>Next, I pushed 2 records into the <code>partition2</code> table and to the same partition (<code>$20170101</code>):</p>
  
  <pre><code>echo '{"a":1, "b":2}' | bq insert '&lt;removed&gt;.partition2$20170101'
  echo '{"a":1, "b":2}' | bq insert '&lt;removed&gt;.partition2$20170101'
  </code></pre>
  
  <p>Again, this looks good:</p>
  
  <p><a href="https://i.stack.imgur.com/f9qaH.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/f9qaH.png" alt="enter image description here"></a></p>
  
  <p>Now, I want to copy append <code>partition2</code> into <code>partition1</code>. I would expect to see 5 records in <code>partition1</code> under the <code>$20170101</code> partition:</p>
  
  <pre><code>bq cp --append_table &lt;removed&gt;.partition2 &lt;removed&gt;.partition1
  Waiting on bqjob_r6d160e17a3b7b733_0000015bb238aa54_1 ... (0s) Current status: DONE   
  Tables '&lt;removed&gt;.partition2' successfully copied to '&lt;removed&gt;.partition1'
  </code></pre>
  
  <p>However, <code>partition1</code> still only has 3 records in it.</p>
  
  <p>What am I doing wrong?</p>