YQL

Yahoo Query Language launched in 2008 with a cheeky premise: treat the web as a single database. With a syntax resembling SQL — SELECT * FROM weather.forecast WHERE location=... — a developer could fetch, filter and join data from different APIs and Yahoo services over one HTTP call, without learning each interface individually.

Open "data tables" let the community add new sources. The idea was elegant and, in spirit, a forerunner of today's unified query layers like GraphQL — but it depended on Yahoo caring enough to run it. Yahoo did not: after the Verizon takeover, YQL was shut down in January 2019, and the API meant to make the web queryable vanished along with its owner.