alter postgres column type code example

Example 1: postgresql change column type

ALTER TABLE assets ALTER COLUMN name TYPE VARCHAR;

Example 2: koalas column type

>>> df = ks.DataFrame({'a': list('abc'),
...                    'b': list(range(1, 4)),
...                    'c': np.arange(3, 6).astype('i1'),
...                    'd': np.arange(4.0, 7.0, dtype='float64'),
...                    'e': [True, False, True],
...                    'f': pd.date_range('20130101', periods=3)},
...                   columns=['a', 'b', 'c', 'd', 'e', 'f'])
>>> df.dtypes
a            object
b             int64
c              int8
d           float64
e              bool
f    datetime64[ns]
dtype: object