Examples
    --------
    Read data from SQL via either a SQL query or a SQL tablename.
    When using a SQLite database only SQL queries are accepted,
    providing only the SQL tablename will result in an error.

    >>> from sqlite3 import connect
    >>> conn = connect(':memory:')
    >>> df = pd.DataFrame(data=[[0, '10/11/12'], [1, '12/11/10']],
    ...                   columns=['int_column', 'date_column'])
    >>> df.to_sql(name='test_data', con=conn)
    2

    >>> pd.read_sql('SELECT int_column, date_column FROM test_data', conn)
       int_column date_column
    0           0    10/11/12
    1           1    12/11/10

    >>> pd.read_sql('test_data', 'postgres:///db_name')  # doctest:+SKIP

    Apply date parsing to columns through the ``parse_dates`` argument
    The ``parse_dates`` argument calls ``pd.to_datetime`` on the provided columns.
    Custom argument values for applying ``pd.to_datetime`` on a column are specified
    via a dictionary format:

    >>> pd.read_sql('SELECT int_column, date_column FROM test_data',
    ...             conn,
    ...             parse_dates={"date_column": {"format": "%d/%m/%y"}})
       int_column date_column
    0           0  2012-11-10
    1           1  2010-11-12
    rX