Document new array functions

CLAUDE.md

@@ -0,0 +1,97 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Development Commands
+
+This is a Docusaurus-based documentation site for QuestDB. Key commands:
+
+### Local Development
+- `yarn start` - Start development server on port 3001
+- `yarn build` - Build production version
+- `yarn serve` - Serve built site locally
+
+### Prerequisites
+- Node.js and Yarn package manager
+- Java (for railroad diagram generation)
+- Python (for railroad diagram scripts)
+
+## Architecture Overview
+
+### Documentation Structure
+- **Source**: Content lives in `/documentation/` directory
+- **Static Assets**: Images, diagrams, and files in `/static/`
+- **Components**: React components for documentation in `/src/components/`
+- **Themes**: Custom Docusaurus theme overrides in `/src/theme/`
+
+### Key Directories
+- `documentation/` - Main documentation content (markdown/MDX files)
+- `documentation/reference/` - API and SQL reference documentation
+- `documentation/guides/` - User guides and tutorials
+- `documentation/concept/` - Conceptual documentation
+- `static/images/` - Documentation images and diagrams
+- `src/components/` - Custom React components for docs
+- `plugins/` - Custom Docusaurus plugins
+
+### Content Organization
+- Documentation uses hierarchical structure with sidebars defined in `documentation/sidebars.js`
+- Supports both `.md` and `.mdx` files
+- Partial files (`.partial.mdx`) are excluded from routing but can be imported
+- Math expressions supported via KaTeX
+- Mermaid diagrams supported
+
+## Documentation Features
+
+### Special Syntax
+- **QuestDB SQL**: Use `questdb-sql` language identifier for syntax highlighting
+- **Railroad Diagrams**: SQL syntax diagrams generated via `scripts/railroad.py`
+- **Math**: LaTeX-style math between `$` (inline) or `$$` (block)
+- **Admonitions**: `:::note`, `:::tip`, `:::info`, `:::warning`, `:::danger`
+
+### Custom Components
+- `<RemoteRepoExample />` - Include code from other QuestDB repositories
+- `<TabItem />` and `<Tabs />` - Tabbed content sections
+- Various custom theme components in `src/theme/`
+
+### Image Optimization
+- Lint-staged hook optimizes images automatically
+- WebP conversion supported via `scripts/webp-converter.sh`
+- Size checking via `scripts/check-size-hook.sh`
+
+## Development Workflow
+
+### Creating Railroad Diagrams
+1. Use [Railroad online editor](https://www.bottlecaps.de/rr/ui) to design
+2. Save syntax to `static/images/docs/diagrams/.railroad`
+3. Run `python3 scripts/railroad.py [name]` to generate SVG
+4. Include generated markdown in documentation
+
+### Content Guidelines
+- Follow existing file naming conventions
+- Use proper admonitions for important information
+- Include code examples with appropriate language identifiers
+- Optimize images before committing (handled automatically by hooks)
+
+### Linting and Formatting
+- ESLint and Prettier configured for code quality
+- JavaScript Standard Style rules enforced
+- Format on save recommended in editor
+- Webpack handles linting during development
+
+## Configuration
+
+### Key Config Files
+- `docusaurus.config.js` - Main Docusaurus configuration
+- `documentation/sidebars.js` - Documentation navigation structure
+- `package.json` - Dependencies and scripts
+- `tailwind.config.js` - Tailwind CSS configuration
+
+### Environment Variables
+- `ALGOLIA_APP_ID` and `ALGOLIA_API_KEY` - Search functionality
+- `NETLIFY` and `CONTEXT` - Build environment detection
+
+## Testing and Deployment
+- Production builds minify CSS and disable update notifiers
+- Preview builds use relaxed error handling
+- Algolia search integration for documentation search
+- PWA support configured with custom manifest

documentation/reference/function/array.md

@@ -70,6 +70,46 @@ SELECT array_cum_sum(ARRAY[ [1.0, 1.0], [2.0, 2.0] ]);
 | ---------------------- |
 | ARRAY[1.0,2.0,4.0,6.0] |
 
+## array_max
+
+`array_max(array)` returns the maximum value from all the array elements. `NULL`
+elements and non-finite values (NaN, Infinity) are ignored. If the array
+contains no finite values, the function returns `NULL`.
+
+#### Parameter
+
+- `array` — the array
+
+#### Example
+
+```questdb-sql
+SELECT array_max(ARRAY[ [1.0, 5.0], [3.0, 2.0] ]);
+```
+
+| array_max |
+| --------- |
+| 5.0       |
+
+## array_min
+
+`array_min(array)` returns the minimum value from all the array elements. `NULL`
+elements and non-finite values (NaN, Infinity) are ignored. If the array
+contains no finite values, the function returns `NULL`.
+
+#### Parameter
+
+- `array` — the array
+
+#### Example
+
+```questdb-sql
+SELECT array_min(ARRAY[ [1.0, 5.0], [3.0, 2.0] ]);
+```
+
+| array_min |
+| --------- |
+| 1.0       |
+
 ## array_position
 
 `array_position(array, elem)` returns the position of `elem` inside the 1D `array`. If
@@ -112,6 +152,71 @@ SELECT array_sum(ARRAY[ [1.0, 1.0], [2.0, 2.0] ]);
 | --------- |
 | 6.0       |
 
+## array_stddev
+
+`array_stddev(array)` returns the sample standard deviation of all the array
+elements. This is an alias for `array_stddev_samp()`. `NULL` elements and
+non-finite values (NaN, Infinity) are ignored. If the array contains fewer than
+2 finite values, the function returns `NULL`.
+
+#### Parameter
+
+- `array` — the array
+
+#### Example
+
+```questdb-sql
+SELECT array_stddev(ARRAY[ [1.0, 2.0], [3.0, 4.0] ]);
+```
+
+| array_stddev |
+| ------------ |
+| 1.29099445   |
+
+## array_stddev_pop
+
+`array_stddev_pop(array)` returns the population standard deviation of all the
+array elements. `NULL` elements and non-finite values (NaN, Infinity) are
+ignored. The population standard deviation uses N in the denominator of the
+standard deviation formula. If the array contains no finite values, the function
+returns `NULL`.
+
+#### Parameter
+
+- `array` — the array
+
+#### Example
+
+```questdb-sql
+SELECT array_stddev_pop(ARRAY[ [1.0, 2.0], [3.0, 4.0] ]);
+```
+
+| array_stddev_pop |
+| ---------------- |
+| 1.11803399       |
+
+## array_stddev_samp
+
+`array_stddev_samp(array)` returns the sample standard deviation of all the
+array elements. `NULL` elements and non-finite values (NaN, Infinity) are
+ignored. The sample standard deviation uses N-1 in the denominator of the
+standard deviation formula. If the array contains fewer than 2 finite values,
+the function returns `NULL`.
+
+#### Parameter
+
+- `array` — the array
+
+#### Example
+
+```questdb-sql
+SELECT array_stddev_samp(ARRAY[ [1.0, 2.0], [3.0, 4.0] ]);
+```
+
+| array_stddev_samp |
+| ----------------- |
+| 1.29099445        |
+
 ## dim_length
 
 `dim_length(array, dim)` returns the length of the n-dimensional array along