Ejemplo n.º 1
0
def _is_ordering_expression(expression):
    """
        Test an expression whether it is an ordering clause
    """

    if hasattr(expression, 'operator') and is_ordering_modifier(expression.operator):
        return True

    if hasattr(expression, 'modifier') and is_ordering_modifier(expression.modifier):
        return True

    return False
Ejemplo n.º 2
0
def _is_ordering_expression(expression):
    """
        Test an expression whether it is an ordering clause
    """

    if hasattr(expression, 'operator') and is_ordering_modifier(expression.operator):
        return True

    if hasattr(expression, 'modifier') and is_ordering_modifier(expression.modifier):
        return True

    return False
Ejemplo n.º 3
0
def unwrap_order_by(clause):
    """Break up an 'order by' expression into individual column-expressions,
    without DESC/ASC/NULLS FIRST/NULLS LAST"""

    cols = util.column_set()
    stack = deque([clause])
    while stack:
        t = stack.popleft()
        if isinstance(t, expression.ColumnElement) and (
            not isinstance(t, expression._UnaryExpression) or not operators.is_ordering_modifier(t.modifier)
        ):
            cols.add(t)
        else:
            for c in t.get_children():
                stack.append(c)
    return cols
Ejemplo n.º 4
0
def unwrap_order_by(clause):
    """Break up an 'order by' expression into individual column-expressions,
    without DESC/ASC/NULLS FIRST/NULLS LAST"""

    cols = util.column_set()
    stack = deque([clause])
    while stack:
        t = stack.popleft()
        if isinstance(t, expression.ColumnElement) and \
            (
                not isinstance(t, expression._UnaryExpression) or \
                not operators.is_ordering_modifier(t.modifier)
            ):
            cols.add(t)
        else:
            for c in t.get_children():
                stack.append(c)
    return cols