Question

我尝试在使用Q对象的过滤器中组合AND和OR。它看起来像|表现得像一个AND。这与先前的注释有关，该注释在同一查询中运行，而不是作为子查询运行。

使用Django处理此问题的正确方法是什么？

models.py

class Type(models.Model):
    name = models.CharField(_('name'), max_length=100)
    stock = models.BooleanField(_('in stock'), default=True)
    hide = models.BooleanField(_('hide'), default=False)
    deleted = models.BooleanField(_('deleted'), default=False)

class Item(models.Model):
    barcode = models.CharField(_('barcode'), max_length=100, blank=True)
    quantity = models.IntegerField(_('quantity'), default=1)
    type = models.ForeignKey('Type', related_name='items', verbose_name=_('type'))

views.py

def hire(request):
    categories_list = Category.objects.all().order_by('sorting')
    types_list = Type.objects.annotate(quantity=Sum('items__quantity')).filter(
        Q(hide=False) & Q(deleted=False),
        Q(stock=False) | Q(quantity__gte=1))
    return render_to_response('equipment/hire.html', {
           'categories_list': categories_list,
           'types_list': types_list,
           }, context_instance=RequestContext(request))

生成的SQL查询

SELECT "equipment_type"."id" [...] FROM "equipment_type" LEFT OUTER JOIN
    "equipment_subcategory" ON ("equipment_type"."subcategory_id" =
    "equipment_subcategory"."id") LEFT OUTER JOIN "equipment_item" ON
    ("equipment_type"."id" = "equipment_item"."type_id") WHERE 
    ("equipment_type"."hide" = False AND "equipment_type"."deleted" = False )
    AND ("equipment_type"."stock" = False )) GROUP BY "equipment_type"."id"
    [...] HAVING SUM("equipment_item"."quantity") >= 1

预期的SQL查询

SELECT
    *
FROM
    equipment_type
LEFT JOIN (
    SELECT type_id, SUM(quantity) AS qty
    FROM equipment_item
    GROUP BY type_id
) T1
ON id = T1.type_id
WHERE hide=0 AND deleted=0 AND (T1.qty > 0 OR stock=0)

编辑：我添加了预期的SQL查询（没有在equipment_subcategory上加入）

Answer 1

尝试添加括号以明确指定您的分组？正如您已经想到的那样，filter()的多个参数只是通过底层SQL中的AND连接。

最初你有这个过滤器：

[...].filter(
    Q(hide=False) & Q(deleted=False),
    Q(stock=False) | Q(quantity__gte=1))

如果你想要（A＆amp; B）＆amp; （C | D）然后这应该工作：

[...].filter(
    Q(hide=False) & Q(deleted=False) &
    (Q(stock=False) | Q(quantity__gte=1)))

Answer 2

好的，这里或#django没有成功。所以我选择使用原始SQL查询来解决这个问题......

这是工作代码：

types_list = Type.objects.raw('SELECT * FROM equipment_type
    LEFT JOIN (                                            
        SELECT type_id, SUM(quantity) AS qty               
        FROM equipment_item                                
        GROUP BY type_id                                   
    ) T1                                                   
    ON id = T1.type_id                                     
    WHERE hide=0 AND deleted=0 AND (T1.qty > 0 OR stock=0) 
    ')

Answer 3

这个答案很晚，但可能会对很多人有所帮助。

[...].filter(hide=False & deleted=False)
.filter(Q(stock=False) | Q(quantity__gte=1))

这将生成类似于

的内容

WHERE (hide=0 AND deleted=0 AND (T1.qty > 0 OR stock=0))

Answer 4

这是我的复杂查询示例，希望对您有帮助

or_condition = Q()
and_condition = Q(company=request.user.profile.company)

for field in MyModel._meta.get_fields():
    if field.name != 'created_on' and field.name != 'company':
        or_condition.add(
            Q(**{"{}__icontains".format(field.name): query}), Q.OR)

and_condition.add(or_condition2, Q.AND)
MyModel.objects.filter(and_condition)

此方法的问题在于，您的empty (AND: )中有一个or_condition的情况。它根本不影响查询，但是让我很烦！我目前的解决方法如下

import operator
from functools import reduce

and_condition = Q(company=request.user.profile.company)
or_condition = reduce(operator.or_, (Q(**{"{}__icontains".format(field.name): query})
                                     for field in MyModel._meta.get_fields() if field.name != 'created_on' and field.name != 'company'))

and_condition.add(or_condition, Q.AND)
MyModel.objects.filter(and_condition)

结合AND和OR与Q对象的Django查询过滤器不返回预期结果

4 个答案: