node.js - Mongoose/node.js 我如何查询范围 [20 到 30 之间的元素]

Question

我的 mongodb 表中有 500 个元素，例如，我只想选择前 100 个元素之后的 100 个元素。为此，请尝试使用 .slice 等。但此查询无法正常工作。我正在使用 Mongoose 和 node.js:

var query2 = JenkinsTestModel.find();
query2.where('jobname date').slice([-100 /*skip*/, 100 /*limit*/]) //i tried several different ways here
query2.exec(function (err, job) {
     if (err) throw err;
     console.log(job);           
});

此查询返回所有元素。我该如何解决上述问题？

Answer 1

您可以使用 skip() 和 limit() 方法:

var query2 = JenkinsTestModel.find()
    .where('jobname date')
    .skip(100)                          
    .limit(100)   
    .exec(function (err, job) {
         if (err) throw err;
         console.log(job);           
    });

注意:来自 docs

The cursor.skip() method is often expensive because it requires the server to walk from the beginning of the collection or index to get the offset or skip position before beginning to return result. As offset (e.g. pageNumber above) increases, cursor.skip() will become slower and more CPU intensive. With larger collections, cursor.skip() may become IO bound.