问题
In my collection posts
I've documents like this
[{
_id : ObjectId("post-object-id"),
title : 'Post #1',
category_id : ObjectId("category-object-id")
}]
I need to make some queries where I those a range of posts based on their category_id (can be multiple ids) but exclude some of them.
I've tried with the query (in shell):
db.posts.find({$and: [
{_id: { $nin : ['ObjectId("post-object-id")']}},
{category_id : { $in : ['ObjectId("category-object-id")']}}
]})
I returns 0 if count().
However, if I change the category_id attribute and remove the $in and just include one ID it work, like this:
db.posts.find({$and: [
{_id: { $nin : ['ObjectId("58a1af81613119002d42ef06")']}},
{category_id : ObjectId("58761634bfb31efd5ce6e88d")}
]})
but this solution only enables me to find by one category.
How would I got about combining $in and $nin with objectId's in the same manner as above?
回答1:
This will work, just remove single quotes around ObjectId
db.posts.find({$and: [
{_id: { $nin : [ObjectId("post-object-id")]}},
{category_id : { $in : [ObjectId("category-object-id")]}}
]})
You should not put single quotes around ObjectId, it make them strings
来源:https://stackoverflow.com/questions/42225802/mongodb-combine-in-and-nin