如何从DB中的每个集合中获取N个文档？

db.getCollectionNames().forEach(function(collectionName) {
    var cursor = db[collectionName].find().limit(N);
    cursor.forEach(function(doc) {
        // 处理每个文档
        printjson(doc);
    });
});

SELECT * FROM table1 LIMIT N;
SELECT * FROM table2 LIMIT N;
-- 重复以上语句，直到覆盖所有表

const MongoClient = require('mongodb').MongoClient;
const url = 'mongodb://localhost:27017';
const dbName = 'mydb';

MongoClient.connect(url, function(err, client) {
    if (err) throw err;
    const db = client.db(dbName);

    db.listCollections().toArray(function(err, collections) {
        if (err) throw err;

        collections.forEach(function(collectionInfo) {
            const collectionName = collectionInfo.name;
            const collection = db.collection(collectionName);
            collection.find().limit(N).toArray(function(err, docs) {
                if (err) throw err;
                // 处理每个集合的文档
                console.log(`Documents from ${collectionName}:`, docs);
            });
        });

        client.close();
    });
});