title: Postgres and jsonb - search value at any key
body: <p>Is possible to look for a given value at any key in a JSONB column in Postgres? <a href="https://www.postgresql.org/docs/9.6/static/functions-json.html" rel="noreferrer">In the documentation</a> I can't see any example.</p>
  
  <p>Example value at a <code>JSONB</code> column:</p>
  
  <pre><code>{
    a: 1,
    b: 2,
    c: 3
  }
  </code></pre>
  
  <p>I want to find all records that have <code>1</code> as a value anywhere. NOTE: there may be other keys than <code>a, b, c</code> unknown at the moment.</p>