title: 'NoneType' object is not iterable Error when using Sqlite3 and python to run query
body: <p>I wanted to create a table in a database on Jupyter Notebook using Python and sqlite3.
  To avoid the table already exists error, I used the following code:</p>
  
  <pre><code>    q1 = '''
      CREATE TABLE IF NOT EXISTS person (
          person_id TEXT PRIMARY KEY,
          first_name TEXT,
          last_name TEXT
      );
  '''
  run_query(q1)
  </code></pre>
  
  <p>However I received this error and I can't get rid of it.</p>
  
  <pre><code>TypeErrorTraceback (most recent call last)
  &lt;ipython-input-25-948d42611e56&gt; in &lt;module&gt;()
        7 
        8 '''
  ----&gt; 9 run_query(q1)
  
  &lt;ipython-input-13-67c680d27fbe&gt; in run_query(q)
        3 def run_query(q):
        4     with sqlite3.connect(db) as conn:
  ----&gt; 5         return pd.read_sql(q,conn)
        6 
        7 def run_command(c):
  
  /dataquest/system/env/python3/lib/python3.4/site-packages/pandas/io/sql.py in read_sql(sql, con, index_col, coerce_float, params, parse_dates, columns, chunksize)
      398             sql, index_col=index_col, params=params,
      399             coerce_float=coerce_float, parse_dates=parse_dates,
  --&gt; 400             chunksize=chunksize)
      401 
      402     try:
  
  /dataquest/system/env/python3/lib/python3.4/site-packages/pandas/io/sql.py in read_query(self, sql, index_col, coerce_float, params, parse_dates, chunksize)
     1443         args = _convert_params(sql, params)
     1444         cursor = self.execute(*args)
  -&gt; 1445         columns = [col_desc[0] for col_desc in cursor.description]
     1446 
     1447         if chunksize is not None:
  
  TypeError: 'NoneType' object is not iterable
  </code></pre>
  
  <p>The table was created when I checked and the columns are there.</p>
  
  <p>Any help would be greatly appreciated.</p>