title: Google Bigquery SQL UNNEST and STRING_AGG
body: <p>I have tried the following query:</p>
  
  <pre><code>SELECT STRING_AGG(inputs.addresses) as stringAgg, 
  FROM `bigquery-public-data.crypto_bitcoin.transactions`
  JOIN UNNEST (inputs) AS inputs
  GROUP BY Date(block_timestamp)
  </code></pre>
  
  <p>However, I get the following error:</p>
  
  <blockquote>
    <p><em>No matching signature for aggregate function STRING_AGG for argument
    types: ARRAY. Supported signatures: STRING_AGG(STRING);
    STRING_AGG(STRING, STRING); STRING_AGG(BYTES); STRING_AGG(BYTES,
    BYTES) at [2:3] Learn More about BigQuery SQL Functions.</em></p>
  </blockquote>
  
  <p>Unsure how to get around this and get the list of addresses that are present in output. Error makes sense given the type addresses is:<br>
  [outputs. addresses STRING  REPEATED    Addresses which own this output. </p>