Question

查询非常复杂（请不要尝试解决示例 - 问题更复杂）

crit=[]
crit.append(Q(firstcond = name) | Q(firstcond__isnull = True)
crit.append(Q(secondcond = name) | Q(firstcond__isnull = True)

MyObject.objects.filter(reduce(operator.and_, crit))

这可以按预期工作：

WHERE (firstcond = name OR firstcond IS NULL) AND (secondcond = name OR secondcond IS NULL)

但现在我需要一些OR：

WHERE ((firstcond = name OR firstcond IS NULL) AND (secondcond = name OR \
secondcond IS NULL)) OR (third = value)

我无法添加第三个int暴击列表，因为operator.and_在reduce中。我必须在reduce之后添加operator._or，但是如何？

Answer 1

无需使用reduce：

crit = (Q(firstcond = name) | Q(firstcond__isnull = True)) & (Q(secondcond = name) | Q(firstcond__isnull = True)) | Q(third = value)
MyObject.objects.filter(crit)

如果您出于某种原因需要reduce：

MyObject.objects.filter(reduce(operator.and_, crit) | Q(third = value))

或者：

MyObject.objects.filter(reduce(operator.or_([reduce(operator.and_, crit), Q(third = value)]))

django Q对象用reduce嵌套

1 个答案: