从NodeJS查询Mongo时,如何在同一个JSON字段上实现逻辑或?
具体来说,我有以下几行:
collection.find({"user":req.user.email, "parent._id":0}, function(err, activities){
if (err) throw err;
res.json(activities);
});
我如何才能正确地包括条目,以便也允许使用"Parent":{}?
下面给出一个空数组:
collection.find({"user":req.user.email, "parent":{}, "parent._id":0}, function(err, activities){
if (err) throw err;
res.json(activities);
});
工作代码:
collection.find({"user":req.user.email, $or:[{"parent._id":0},{"parent":{}}]}, function(err, activities){
if (err) throw err;
res.json(activities);
});