title: How to filter by "literal in column" in sqlalchemy
body: <p>It is possible to filter by checking if a column is <code>in</code> a literal
  using the <code>in_</code> column operator of SQLAlchemy - <a href="https://docs.sqlalchemy.org/en/13/core/sqlelement.html#sqlalchemy.sql.operators.ColumnOperators.in_" rel="nofollow noreferrer">doc</a></p>
  <p><code>filter(COL.in_(1,2,3))</code> is converted to SQL <code>WHERE COL IN (1, 2, 3)</code>
  which filters by checking if a column is <code>in</code> a literal</p>
  <p>I am searching for a way to filter by checking if a literal is <code>in</code> a column, where the column is of type array (or repeated field in BigQuery)</p>
  <p>Is there an SQLAlchemy construct in which it is possible to create a filter similar to the following SQL (BigQuery Standard)</p>
  <pre><code>WHERE 1 in UNNEST(COL)
  </code></pre>
  <p>A very similar query in PostgreSQL and the expected results can be seen <a href="https://www.db-fiddle.com/f/mUTWMbFapc3cLxcbvzUDZ6/0" rel="nofollow noreferrer">here</a></p>