我们从Python开源项目中,提取了以下9个代码示例,用于说明如何使用sqlalchemy.func.bernoulli()。
def tablesample(selectable, sampling, name=None, seed=None): """Return a :class:`.TableSample` object. :class:`.TableSample` is an :class:`.Alias` subclass that represents a table with the TABLESAMPLE clause applied to it. :func:`~.expression.tablesample` is also available from the :class:`.FromClause` class via the :meth:`.FromClause.tablesample` method. The TABLESAMPLE clause allows selecting a randomly selected approximate percentage of rows from a table. It supports multiple sampling methods, most commonly BERNOULLI and SYSTEM. e.g.:: from sqlalchemy import func selectable = people.tablesample( func.bernoulli(1), name='alias', seed=func.random()) stmt = select([selectable.c.people_id]) Assuming ``people`` with a column ``people_id``, the above statement would render as:: SELECT alias.people_id FROM people AS alias TABLESAMPLE bernoulli(:bernoulli_1) REPEATABLE (random()) .. versionadded:: 1.1 :param sampling: a ``float`` percentage between 0 and 100 or :class:`.functions.Function`. :param name: optional alias name :param seed: any real-valued SQL expression. When specified, the REPEATABLE sub-clause is also rendered. """ return _interpret_as_from(selectable).tablesample( sampling, name=name, seed=seed)