base on A query builder for PostgreSQL, MySQL, CockroachDB, SQL Server, SQLite3 and Oracle, designed to be flexible, portable, and fun to use. # [knex.js](https://knex.github.io/documentation/) [](https://npmjs.org/package/knex) [](https://npmjs.org/package/knex)  [](https://coveralls.io/r/knex/knex?branch=master) [](https://libraries.io/npm/knex) [](https://gitter.im/tgriesser/knex) > **A SQL query builder that is _flexible_, _portable_, and _fun_ to use!** A batteries-included, multi-dialect (PostgreSQL, MySQL, CockroachDB, MSSQL, SQLite3, Oracle (including Oracle Wallet Authentication)) query builder for Node.js, featuring: - [transactions](https://knex.github.io/documentation/#Transactions) - [connection pooling](https://knex.github.io/documentation/#Installation-pooling) - [streaming queries](https://knex.github.io/documentation/#Interfaces-Streams) - both a [promise](https://knex.github.io/documentation/#Interfaces-Promises) and [callback](https://knex.github.io/documentation/#Interfaces-Callbacks) API - a [thorough test suite](https://github.com/knex/knex/actions) Node.js versions 12+ are supported. - Take a look at the [full documentation](https://knex.github.io/documentation) to get started! - Browse the [list of plugins and tools](https://github.com/knex/knex/blob/master/ECOSYSTEM.md) built for knex - Check out our [recipes wiki](https://github.com/knex/knex/wiki/Recipes) to search for solutions to some specific problems - In case of upgrading from an older version, see [migration guide](https://github.com/knex/knex/blob/master/UPGRADING.md) You can report bugs and discuss features on the [GitHub issues page](https://github.com/knex/knex/issues) or send tweets to [@kibertoad](http://twitter.com/kibertoad). For support and questions, join our [Gitter channel](https://gitter.im/tgriesser/knex). For knex-based Object Relational Mapper, see: - https://github.com/Vincit/objection.js - https://github.com/mikro-orm/mikro-orm - https://bookshelfjs.org To see the SQL that Knex will generate for a given query, you can use [Knex Query Lab](https://michaelavila.com/knex-querylab/) ## Examples We have several examples [on the website](http://knexjs.org). Here is the first one to get you started: ```js const knex = require('knex')({ client: 'sqlite3', connection: { filename: './data.db', }, }); try { // Create a table await knex.schema .createTable('users', (table) => { table.increments('id'); table.string('user_name'); }) // ...and another .createTable('accounts', (table) => { table.increments('id'); table.string('account_name'); table.integer('user_id').unsigned().references('users.id'); }); // Then query the table... const insertedRows = await knex('users').insert({ user_name: 'Tim' }); // ...and using the insert id, insert into the other table. await knex('accounts').insert({ account_name: 'knex', user_id: insertedRows[0], }); // Query both of the rows. const selectedRows = await knex('users') .join('accounts', 'users.id', 'accounts.user_id') .select('users.user_name as user', 'accounts.account_name as account'); // map over the results const enrichedRows = selectedRows.map((row) => ({ ...row, active: true })); // Finally, add a catch statement } catch (e) { console.error(e); } ``` ## TypeScript example ```ts import { Knex, knex } from 'knex'; interface User { id: number; age: number; name: string; active: boolean; departmentId: number; } const config: Knex.Config = { client: 'sqlite3', connection: { filename: './data.db', }, }; const knexInstance = knex(config); try { const users = await knex<User>('users').select('id', 'age'); } catch (err) { // error handling } ``` ## Usage as ESM module If you are launching your Node application with `--experimental-modules`, `knex.mjs` should be picked up automatically and named ESM import should work out-of-the-box. Otherwise, if you want to use named imports, you'll have to import knex like this: ```js import { knex } from 'knex/knex.mjs'; ``` You can also just do the default import: ```js import knex from 'knex'; ``` If you are not using TypeScript and would like the IntelliSense of your IDE to work correctly, it is recommended to set the type explicitly: ```js /** * @type {Knex} */ const database = knex({ client: 'mysql', connection: { host: '127.0.0.1', user: 'your_database_user', password: 'your_database_password', database: 'myapp_test', }, }); database.migrate.latest(); ``` ", Assign "at most 3 tags" to the expected json: {"id":"1337","tags":[]} "only from the tags list I provide: [{"id":77,"name":"3d"},{"id":89,"name":"agent"},{"id":17,"name":"ai"},{"id":54,"name":"algorithm"},{"id":24,"name":"api"},{"id":44,"name":"authentication"},{"id":3,"name":"aws"},{"id":27,"name":"backend"},{"id":60,"name":"benchmark"},{"id":72,"name":"best-practices"},{"id":39,"name":"bitcoin"},{"id":37,"name":"blockchain"},{"id":1,"name":"blog"},{"id":45,"name":"bundler"},{"id":58,"name":"cache"},{"id":21,"name":"chat"},{"id":49,"name":"cicd"},{"id":4,"name":"cli"},{"id":64,"name":"cloud-native"},{"id":48,"name":"cms"},{"id":61,"name":"compiler"},{"id":68,"name":"containerization"},{"id":92,"name":"crm"},{"id":34,"name":"data"},{"id":47,"name":"database"},{"id":8,"name":"declarative-gui "},{"id":9,"name":"deploy-tool"},{"id":53,"name":"desktop-app"},{"id":6,"name":"dev-exp-lib"},{"id":59,"name":"dev-tool"},{"id":13,"name":"ecommerce"},{"id":26,"name":"editor"},{"id":66,"name":"emulator"},{"id":62,"name":"filesystem"},{"id":80,"name":"finance"},{"id":15,"name":"firmware"},{"id":73,"name":"for-fun"},{"id":2,"name":"framework"},{"id":11,"name":"frontend"},{"id":22,"name":"game"},{"id":81,"name":"game-engine "},{"id":23,"name":"graphql"},{"id":84,"name":"gui"},{"id":91,"name":"http"},{"id":5,"name":"http-client"},{"id":51,"name":"iac"},{"id":30,"name":"ide"},{"id":78,"name":"iot"},{"id":40,"name":"json"},{"id":83,"name":"julian"},{"id":38,"name":"k8s"},{"id":31,"name":"language"},{"id":10,"name":"learning-resource"},{"id":33,"name":"lib"},{"id":41,"name":"linter"},{"id":28,"name":"lms"},{"id":16,"name":"logging"},{"id":76,"name":"low-code"},{"id":90,"name":"message-queue"},{"id":42,"name":"mobile-app"},{"id":18,"name":"monitoring"},{"id":36,"name":"networking"},{"id":7,"name":"node-version"},{"id":55,"name":"nosql"},{"id":57,"name":"observability"},{"id":46,"name":"orm"},{"id":52,"name":"os"},{"id":14,"name":"parser"},{"id":74,"name":"react"},{"id":82,"name":"real-time"},{"id":56,"name":"robot"},{"id":65,"name":"runtime"},{"id":32,"name":"sdk"},{"id":71,"name":"search"},{"id":63,"name":"secrets"},{"id":25,"name":"security"},{"id":85,"name":"server"},{"id":86,"name":"serverless"},{"id":70,"name":"storage"},{"id":75,"name":"system-design"},{"id":79,"name":"terminal"},{"id":29,"name":"testing"},{"id":12,"name":"ui"},{"id":50,"name":"ux"},{"id":88,"name":"video"},{"id":20,"name":"web-app"},{"id":35,"name":"web-server"},{"id":43,"name":"webassembly"},{"id":69,"name":"workflow"},{"id":87,"name":"yaml"}]" returns me the "expected json"