MongoDB合并两个相同的架构集合

我正在使用带有node express的mongoDB，我在我的db中有两个名称为“user”和“user_archive”的集合。我想在查询中合并两个集合数据，并希望执行分页。

对于单一集合分页，我使用下面的代码：

user.find(condition)
        .select()
        .limit(perPage)
        .skip(perPage * page)
        .sort(sortObject)
        .exec(function(err, data)
        {
                callback(err,data);

        });

我想通过合并user和user_archive集合数据来执行分页。

用户集合

{"name":A}
{"name": B}

user_archive集合

{"name":C}
{"name":D}

我需要合并下面的两个集合，然后想要执行分页：

{"name":A}
{"name":B}
{"name":C}
{"name":D}

任何人都可以建议我如何在我的代码中这样做。

您可以使用聚合管道。例如

用户集合

{ "_id": "1", "email": "[email protected]", "fullName": "Jon1"},
{ "_id": "2", "email": "[email protected]", "fullName": "Jon2"},
{ "_id": "3", "email": "[email protected]", "fullName": "Jon3"}

邮政集合

{ "_id": "11", "owner": "1", "content": "text1"},
{ "_id": "12", "owner": "2", "content": "text2"},
{ "_id": "13", "owner": "3", "content": "text3"},

.

async function getData (options) {
let query = [];

// merge posts and users
query.push(
    { $lookup: { from: 'posts', localField: '_id', foreignField: 'owner', as: 'posts' } }
);

// pagination
if (options.page && options.size) {
    let skip = options.size * (options.page - 1);

    query.push(
        { $skip: skip },
        { $limit: options.size }
    );
}

return await db.posts.aggregate(query);

}

这个函数的结果将是

{ "_id": "11", "owner": { "_id": "1", "email": "[email protected]", "fullName": "Jon1" }, "content": "text1"},
{ "_id": "12", "owner": { "_id": "2", "email": "[email protected]", "fullName": "Jon2" }, "content": "text2"},
{ "_id": "13", "owner": { "_id": "3", "email": "[email protected]", "fullName": "Jon3" }, "content": "text3"}

例如，如果options = {page：1，size：2}，则结果为

{ "_id": "11", "owner": { "_id": "1", "email": "[email protected]", "fullName": "Jon1" }, "content": "text1"},
{ "_id": "12", "owner": { "_id": "2", "email": "[email protected]", "fullName": "Jon2" }, "content": "text2"},