title: SQL - Nested query optimization
body: <p>How can I optimize this query SQL?</p>
  
  <pre><code>CREATE TABLE table1 AS
   SELECT * FROM temp
   WHERE Birth_Place IN
     (SELECT c.DES_COM
        FROM tableCom AS c
        WHERE c.COD_PROV IS NULL)
   ORDER BY Cod, Birth_Date
  </code></pre>
  
  <p>I think that the problem is the <code>IN</code> clause</p>