GQL Reference for Appengine

Anyone have a good reference guide for GQL (query language for google appengine datastore)?

I开发者_JAVA百科 find the reference guide on the google appengine site very limited with examples

The doc is limited because GQL is a very, very simple query language, intended to provided an SQL-like interface on top of protocol buffers. There's not a lot of complexity to it.

The most instructive thing may be to read the GQL source. It's online here. Note in particular how GQL is parsed with a simple, hand-rolled top-down parser.