def sql_to_dataframe(conn, query, column_names):
   “”” 
   Import data from a PostgreSQL database using a SELECT query 
   “””
   cursor = conn.cursor()
   try:
      cursor.execute(query)
   except (Exception, psycopg2.DatabaseError) as error:
      print(“Error: %s” % error)
   cursor.close()
   return 1
   # The execute returns a list of tuples:
   tuples_list = cursor.fetchall()
   cursor.close()
   # Now we need to transform the list into a pandas DataFrame:
   df = pd.DataFrame(tuples_list, columns=column_names)
   return df