Question

我正在尝试查询具有适合给定用户计划的学习课程的组。为什么以下查询不起作用？

Group.find().or([
  {$and: [ {mondayStart: {lte: 6}}, {mondayEnd:  {gte: 8}}] },
  {$and: [ {tuesdayStart: {lte: 9}}, {tuesdayEnd: {gte:13}}] },
  {$and: [ {wednesdayStart: {lte: 9}}, {wednesdayEnd: {gte: 12}}]
])


const mongoose = require('mongoose');
const Schema = mongoose.Schema;

const GroupSchema = new Schema({
  owner: {type: mongoose.Schema.ObjectId, ref: 'users'},
  subject: String,
  date: {type: Date, default: Date.now},
  mondayStart: Number,
  mondayEnd: Number,
  tuesdayStart: Number,
  tuesdayEnd: Number,
  wednesdayStart: Number,
  wednesdayEnd: Number
});

module.exports = Group = mongoose.model('groups', GroupSchema);

Answer 1

您必须执行查询才能使其“返回”某些东西。

const query = Group.find().or([
    {$and: [{mondayStart: {lte: 6}}, {mondayEnd: {gte: 8}}]},
    {$and: [{tuesdayStart: {lte: 9}}, {tuesdayEnd: {gte: 13}}]},
    {$and: [{wednesdayStart: {lte: 9}}, {wednesdayEnd: {gte: 12}}]}
]);

可以通过Query.prototype.exec()执行Query：

// Using a callback
query.exec((err, groups) => {
    if (err) console.error(err);
    else console.log(groups);
});

// As a promise
query.exec().then((groups) => {
    console.log(groups);
}).catch((err) => {
    console.error(err);
});

// As a promise using async/await
try {
    const groups = await query.exec();
    console.log(groups);
} catch (err) {
    console.error(err);
}

或通过调用Query.prototype.then()（隐式执行查询）：

// Using then
query.then((groups) => {
    console.log(groups);
}).catch((err) => {
    console.error(err);
});

// Using async/await
try {
    const groups = await query;
    console.log(groups);
} catch (err) {
    console.error(err);
}

猫鼬或查询不返回任何内容

1 个答案: