eKuiper offers a SQL-like query language for performing transformations and computations over streams of events. This document describes the syntax, usage and best practices for the eKuiper query language. 

- [Stream specifications](streams.md)
- [Query languange element](query_language_elements.md)
- [Windows](windows.md)
- [Built-in functions](built-in_functions.md)
- Extension
  - [Plugin extension](../extension/overview.md)
  - [External service extension](../extension/external/external_func.md)