ZetaSQL defines a SQL language (grammar, types, data model, semantics, and function library) and implements parsing and analysis for that language as a reusable component. ZetaSQL is not itself a database or query engine. Instead, it's intended to be used by multiple engines, to provide consistent language and behavior (name resolution, type checking, implicit casting, etc.). Specific query engines may implement a subset of features, giving errors for unsupported features. ZetaSQL's compliance...