如何在lte/gte比较中包含"None"？

Question

我有这种复杂的过滤机制......

d = copy(request.GET)
d.setdefault('sort_by', 'created')
d.setdefault('sort_dir', 'desc')
form = FilterShipmentForm(d)
filter = {
    'status': ShipmentStatuses.ACTIVE
}
exclude = {}
if not request.user.is_staff:
    filter['user__is_staff'] = False

if request.user.is_authenticated():
    exclude['user__blocked_by__blocked'] = request.user

if form.is_valid():
    d = form.cleaned_data
    if d.get('pickup_city'): filter['pickup_address__city__icontains'] = d['pickup_city']
    if d.get('dropoff_city'): filter['dropoff_address__city__icontains'] = d['dropoff_city']
    if d.get('pickup_province'): filter['pickup_address__province__exact'] = d['pickup_province']
    if d.get('dropoff_province'): filter['dropoff_address__province__exact'] = d['dropoff_province']
    if d.get('pickup_country'): filter['pickup_address__country__exact'] = d['pickup_country']
    if d.get('dropoff_country'): filter['dropoff_address__country__exact'] = d['dropoff_country']
    if d.get('min_price'): filter['target_price__gte'] = d['min_price']
    if d.get('max_price'): filter['target_price__lte'] = d['max_price']
    if d.get('min_distance'): filter['distance__gte'] = d['min_distance'] * 1000
    if d.get('max_distance'): filter['distance__lte'] = d['max_distance'] * 1000
    if d.get('available_on'): # <--- RELEVANT BIT HERE ---
        filter['pickup_earliest__lte'] = d['available_on'] # basically I want "lte OR none"
        filter['pickup_latest__gte'] = d['available_on']
    if d.get('shipper'): filter['user__username__iexact'] = d['shipper']

order = ife(d['sort_dir'] == 'desc', '-') + d['sort_by']

shipments = Shipment.objects.filter(**filter).exclude(**exclude).order_by(order) \
    .annotate(num_bids=Count('bids'), min_bid=Min('bids__amount'), max_bid=Max('bids__amount'))

现在我的客户告诉我,他希望提货/送货日期是"灵活的"选项.所以我已经更新了数据库,为此目的允许日期为NULL,但现在"可用于拾取"过滤器将无法按预期工作.它应该包括NULL/None日期.这有一个简单的解决方案吗？

Answer 1

翻转逻辑并使用exclude().您真正想要做的是排除任何指定不适合的日期的数据.如果pickup_latest和pickup_earliest是NULL它不应该匹配排除查询并不会被删除.例如

exclude['pickup_latest__lt'] = d['available_on']
exclude['pickup_earliest__gt'] = d['available_on']

Answer 2

大多数数据库引擎不喜欢与NULL值进行关系比较。用于<field>__isnull显式检查某个值是否NULL在数据库中，但您需要将Q对象与OR条件一起使用。