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# This file is part of python-sql. The COPYRIGHT file at the top level of
# this repository contains the full copyright notices and license terms.
from sql import Expression, Flavor, Literal, Window
__all__ = ['Avg', 'BitAnd', 'BitOr', 'BoolAnd', 'BoolOr', 'Count', 'Every',
'Max', 'Min', 'Stddev', 'Sum', 'Variance']
_sentinel = object()
class Aggregate(Expression):
__slots__ = ('expression', '_distinct', '_order_by', '_within',
'_filter', '_window')
_sql = ''
def __init__(self, expression, distinct=False, order_by=None, within=None,
filter_=None, window=None):
super(Aggregate, self).__init__()
self.expression = expression
self.distinct = distinct
self.order_by = order_by
self.within = within
self.filter_ = filter_
self.window = window
@property
def distinct(self):
return self._distinct
@distinct.setter
def distinct(self, value):
assert isinstance(value, bool)
self._distinct = value
@property
def order_by(self):
return self._order_by
@order_by.setter
def order_by(self, value):
if value is not None:
if isinstance(value, Expression):
value = [value]
assert all(isinstance(col, Expression) for col in value)
self._order_by = value
@property
def within(self):
return self._within
@within.setter
def within(self, value):
if value is not None:
if isinstance(value, Expression):
value = [value]
assert all(isinstance(col, Expression) for col in value)
self._within = value
@property
def filter_(self):
return self._filter
@filter_.setter
def filter_(self, value):
from sql.operators import And, Or
if value is not None:
assert isinstance(value, (Expression, And, Or))
self._filter = value
@property
def window(self):
return self._window
@window.setter
def window(self, value):
if value:
assert isinstance(value, Window)
self._window = value
@property
def _case_expression(self):
return self.expression
def __str__(self):
quantifier = 'DISTINCT ' if self.distinct else ''
has_filter = Flavor.get().filter_
expression = self.expression
if self.filter_ and not has_filter:
from sql.conditionals import Case
expression = Case((self.filter_, self._case_expression))
order_by = ''
if self.order_by:
order_by = ' ORDER BY %s' % ', '.join(map(str, self.order_by))
aggregate = '%s(%s%s%s)' % (
self._sql, quantifier, expression, order_by)
within = ''
if self.within:
within = (' WITHIN GROUP (ORDER BY %s)'
% ', '.join(map(str, self.within)))
filter_ = ''
if self.filter_ and has_filter:
filter_ = ' FILTER (WHERE %s)' % self.filter_
window = ''
if self.window:
if self.window.has_alias:
window = ' OVER "%s"' % self.window.alias
else:
window = ' OVER (%s)' % self.window
return aggregate + within + filter_ + window
@property
def params(self):
has_filter = Flavor.get().filter_
p = []
if self.filter_ and not has_filter:
p.extend(self.filter_.params)
p.extend(self._case_expression.params)
else:
p.extend(self.expression.params)
if self.order_by:
for expression in self.order_by:
p.extend(expression.params)
if self.within:
for expression in self.within:
p.extend(expression.params)
if self.filter_ and has_filter:
p.extend(self.filter_.params)
if self.window and not self.window.has_alias:
p.extend(self.window.params)
return tuple(p)
class Avg(Aggregate):
__slots__ = ()
_sql = 'AVG'
class BitAnd(Aggregate):
__slots__ = ()
_sql = 'BIT_AND'
class BitOr(Aggregate):
__slots__ = ()
_sql = 'BIT_OR'
class BoolAnd(Aggregate):
__slots__ = ()
_sql = 'BOOL_AND'
class BoolOr(Aggregate):
__slots__ = ()
_sql = 'BOOL_OR'
class Count(Aggregate):
__slots__ = ()
_sql = 'COUNT'
def __init__(self, expression=_sentinel, **kwargs):
if expression is _sentinel:
expression = Literal('*')
super().__init__(expression, **kwargs)
@property
def _case_expression(self):
expression = super(Count, self)._case_expression
if (isinstance(self.expression, Literal)
and expression.value == '*'):
expression = Literal(1)
return expression
class Every(Aggregate):
__slots__ = ()
_sql = 'EVERY'
class Max(Aggregate):
__slots__ = ()
_sql = 'MAX'
class Min(Aggregate):
__slots__ = ()
_sql = 'MIN'
class Stddev(Aggregate):
__slots__ = ()
_sql = 'Stddev'
class Sum(Aggregate):
__slots__ = ()
_sql = 'SUM'
class Variance(Aggregate):
__slots__ = ()
_sql = 'VARIANCE'
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