WeChat small program cloud development service-side database API query filtering criteria

db.command.eq

A query filter that means that a field is equal to a value. The eq instruction accepts a literal amount, which can be number, boolean, string, object, array.

Method signature:

function eq(value: any): Command

For example, filter out all your own published articles, except in the form of a pass-through:

const myOpenID = 'xxx'
db.collection('articles').where({
  _openid: myOpenID
})

You can also use instructions:

const _ = db.command
const myOpenID = 'xxx'
db.collection('articles').where({
  _openid: _.eq(openid)
})

Note that eq instructions are more flexible than the way objects are used to indicate that a field is equal to an object, such as:

// 这种写法表示匹配 stat.publishYear == 2018 且 stat.language == 'zh-CN'
db.collection('articles').where({
  stat: {
    publishYear: 2018,
    language: 'zh-CN'
  }
})
// 这种写法表示 stat 对象等于 { publishYear: 2018, language: 'zh-CN' }
const _ = db.command
db.collection('articles').where({
  stat: _.eq({
    publishYear: 2018,
    language: 'zh-CN'
  })
})

The sample code

const cloud = require('wx-server-sdk')
cloud.init()
const db = cloud.database()
const _ = db.command
exports.main = async (event, context) => {
  try {
    return await db.collection('articles').where({
      stat: _.eq({
        publishYear: 2018,
        language: 'zh-CN'
      })
    })
    .get()
  } catch(e) {
    console.error(e)
  }
}

---

db.command.neq

Indicates that the field is not equal to a value, as opposed to db.command.eq

---

db.command.lt

Query filters that indicate that the field needs to be less than the specified value.

Method signature:

function lt(value: number): Command

The sample code

Find todos with a progress of less than 50

const cloud = require('wx-server-sdk')
cloud.init()
const db = cloud.database()
const _ = db.command
exports.main = async (event, context) => {
  try {
    return await db.collection('todos').where({
      progress: _.lt(50)
    })
    .get()
  } catch(e) {
    console.error(e)
  }
}

---

db.command.lte

A query filter that indicates that a field needs to be less than or equal to the specified value.

Method signature:

function lte(value: number): Command

The sample code

Find todos with progress of less than or equal to 50

const cloud = require('wx-server-sdk')
cloud.init()
const db = cloud.database()
const _ = db.command
exports.main = async (event, context) => {
  try {
    return await db.collection('todos').where({
      progress: _.lte(50)
    })
    .get()
  } catch(e) {
    console.error(e)
  }
}

---

db.command.gt

Query filter, which means that the field needs to be greater than the specified value.

Method signature:

function gt(value: number): Command

The sample code

Find todos with progress greater than 50

const cloud = require('wx-server-sdk')
cloud.init()
const db = cloud.database()
const _ = db.command
exports.main = async (event, context) => {
  try {
    return await db.collection('todos').where({
      progress: _.gt(50)
    })
    .get()
  } catch(e) {
    console.error(e)
  }
}

---

db.command.gte

A query filter that indicates that a field needs to be greater than or equal to the specified value.

Method signature:

function gte(value: number): Command

The sample code

Find todos with progress greater than or equal to 50

const cloud = require('wx-server-sdk')
cloud.init()
const db = cloud.database()
const _ = db.command
exports.main = async (event, context) => {
  try {
    return await db.collection('todos').where({
      progress: _.gte(50)
    })
    .get()
  } catch(e) {
    console.error(e)
  }
}

---

db.command.in

A query filter that indicates that the value of a field needs to be within a given array.

Method signature:

function in(values: any[]): Command

The sample code

Find todos with a progress of 0 or 100

const cloud = require('wx-server-sdk')
cloud.init()
const db = cloud.database()
const _ = db.command
exports.main = async (event, context) => {
  try {
    return await db.collection('todos').where({
      progress: _.in([0, 100])
    })
    .get()
  } catch(e) {
    console.error(e)
  }
}

---

db.command.in

A query filter that indicates that the value of a field needs to be not in a given array.

Method signature:

function nin(values: any[]): Command

The sample code

Find out if the progress is not 0 or 100 todo

const cloud = require('wx-server-sdk')
cloud.init()
const db = cloud.database()
const _ = db.command
exports.main = async (event, context) => {
  try {
    return await db.collection('todos').where({
      progress: _.nin([0, 100])
    })
    .get()
  } catch(e) {
    console.error(e)
  }
}

db.command.nin

Support: small programs, cloud functions, web

The query filter operator, which means that the required value is not in a given array.

Parameters

value: any[]

Returns a value

Command

The sample code

Find out if the progress is not 0 or 100 todo

const _ = db.command
db.collection('todos').where({
  progress: _.nin([0, 100])
})
.get({
  success: console.log,
  fail: console.error
})