SQL in JavaScript (web browser)

 AlaSQL/alasql: AlaSQL.js - JavaScript SQL database for browser and Node.js. Handles both traditional relational tables and nested JSON data (NoSQL). Export, store, and import data from localStorage, IndexedDB, or Excel.

AlaSQL - ( à la SQL ) [ælæ ɛskju:ɛl] - is an open source SQL database for JavaScript with a strong focus on query speed and data source flexibility for both relational data and schemaless data. It works in the web browser, Node.js, and mobile apps.