Claude Code Skills·Claude Skills·The open SKILL.md registry for Claude
ClaudSkills / Science & Research / math-stats

Extended Statistics

Category: Science & Research  ·  Sub-category: math-stats  ·  Last updated:
PostgreSQL's extended statistics — `CREATE STATISTICS`, `pg_statistic_ext`, `pg_statistic_ext_data` — the 4 stat kinds (dependencies / ndistinct / mcv / expressions) that help the planner handle correlated columns, multi-column NDVs, and expression cardinality. Covers `src/backend/statistics/extended_stats.c` + `dependencies.c` + `mcv.c` + `mvdistinct.c`. Loads when the user asks about extended stats syntax, when to `CREATE STATISTICS`, why a query has bad estimates on correlated columns, ndistinct for GROUP BY estimation, MCV lists in the extended-stats context, or the planner's `clauselist_selectivity_ext` selectivity path. Skip when the ask is about `pg_statistic` (single-column stats — the sibling; see `analyze-block-and-reservoir-sampling` idiom) or about ANALYZE mechanics (that's `analyze.c` — different code path).
Security AStatic scan found no risk patternsHow grading works ›

From the source SKILL.md

Column stats live in pg_statistic (one row per column). But real queries often have correlated columns (state = 'CA' AND city = 'SF' — where state and city aren't independent) or expression predicates (WHERE lower(name) = 'alice') that per-column stats can't estimate accurately.

What this skill does

Extended Statistics is a community-contributed Claude Code skill in the math-stats sub-category. It ships as a SKILL.md file that Claude Code auto-discovers under ~/.claude/skills/extended-statistics/ and loads when your prompt matches the skill's trigger.

Who uses this skill

The Extended Statistics Claude Code skill is built for researchers, data scientists, academics, and analysts working with complex data and scientific literature. It's part of ClaudSkills (also referred to as Claude Skills or Claude Code Skills) — the open community-curated registry of 161,000+ SKILL.md files for Anthropic's Claude Code agent and the wider Claude ecosystem (Claude API, Claude Agent SDK).

How to install

Free

Manual install (2 steps)

mkdir -p ~/.claude/skills/extended-statistics
curl -L https://claudskills.com/skills/extended-statistics/SKILL.md \
  -o ~/.claude/skills/extended-statistics/SKILL.md

Or just download SKILL.md directly and drop it into ~/.claude/skills/extended-statistics/. Claude Code auto-discovers it on next session.

Skills live at ~/.claude/skills/extended-statistics/SKILL.md on macOS/Linux, or %USERPROFILE%\.claude\skills\extended-statistics\SKILL.md on Windows. See the full install guide for step-by-step instructions.

Telegram

📱 Install from your phone or desktop Telegram

Open @claudskills_bot on Telegram, tap Open Desktop App, and the desktop app installs this skill for you. Or share the bot link with a colleague — they get the same one-tap install. Learn more →

Pro

One-click install via the desktop app

The ClaudSkills desktop app installs any skill directly into ~/.claude/skills/ with one click — no terminal required. Pro starts at $9/mo or $149 lifetime.

Pro

For the full experience including quality scoring and one-click install features for each skill — upgrade to Pro.

See pricing → Download desktop app

Frequently asked questions

How do I install the Extended Statistics Claude Code skill?
Install via the ClaudSkills desktop app (one click) or copy SKILL.md from the source repository to ~/.claude/skills/extended-statistics/SKILL.md and restart Claude Code. Both flows are detailed at claudskills.com/install/.
What does the Extended Statistics skill do?
PostgreSQL's extended statistics — `CREATE STATISTICS`, `pg_statistic_ext`, `pg_statistic_ext_data` — the 4 stat kinds (dependencies / ndistinct / mcv / expressions) that help the planner handle correlated columns, multi-column NDVs, and expression cardinality. Covers `src/backend/statistics/extended_stats.c` + `dependencies.c` + `mcv.c` + `mvdistinct.c`. Loads when the user asks about extended stats syntax, when to `CREATE STATISTICS`, why a query has bad estimates on correlated columns, ndistinct for GROUP BY estimation, MCV lists in the extended-stats context, or the planner's `clauselist_selectivity_ext` selectivity path. Skip when the ask is about `pg_statistic` (single-column stats — the sibling; see `analyze-block-and-reservoir-sampling` idiom) or about ANALYZE mechanics (that's `analyze.c` — different code path).
Is this skill free to install?
Yes. ClaudSkills is an open registry — every skill keeps its source repository's license, and manual install via copy is free. ClaudSkills Pro ($9/mo, $79/yr, or $149 one-time) adds one-click install via the desktop app and a multi-signal Quality Score.
When should I use the Extended Statistics skill?
Use Extended Statistics when your Claude Code task falls under the Science & Research category — specifically in the math stats area. Claude Code auto-discovers installed skills and invokes the right one based on the task description, so you can also ask Claude directly (e.g. "use Extended Statistics" or describe the task and let Claude pick). Browse related skills at /category/science/.
What is a Claude Code skill and how does the Extended Statistics skill fit in?
A Claude Code skill is a SKILL.md file that lives under ~/.claude/skills/<name>/ and tells the Claude Code CLI agent how to perform a specific task (instructions, prompts, allowed tools). Skills are auto-discovered at session start. Extended Statistics is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the Science & Research category. Learn more at /learn/what-is-a-claude-skill/.

Attribution & license

Cite this skill

If you reference this skill in a blog post, paper, or documentation, you can cite it as:

APA
matejformanek. (2026). Extended Statistics [Claude Code skill]. ClaudSkills. https://claudskills.com/skills/extended-statistics/
BibTeX
@misc{extended-statistics-2026,
  author    = {matejformanek},
  title     = {Extended Statistics [Claude Code skill]},
  year      = {2026},
  publisher = {ClaudSkills},
  url       = {https://claudskills.com/skills/extended-statistics/}
}

Embed this skill

Promote, attribute, or link this skill from your own README, blog post, or documentation. All three snippets are free to use — no sign-up, no API key. More distribution surfaces →

Badge
[![ClaudSkills](https://claudskills.com/badge/extended-statistics.svg)](https://claudskills.com/skills/extended-statistics/?utm_source=badge&utm_medium=readme&utm_campaign=skill_badge)
<script>
<script src="https://claudskills.com/embed/extended-statistics.js" async></script>
<iframe>
<iframe src="https://claudskills.com/embed/extended-statistics.html" width="100%" height="160" frameborder="0" loading="lazy" title="ClaudSkills: Extended Statistics"></iframe>

Security scan

Grade A · scanned 2026-07-26 — free static scan against the OWASP Agentic Skills Top 10.

No risk patterns were found in any of the ten OWASP-aligned categories. How grading works ›

Show this grade on your repo (click to copy):

[![Security: A](https://img.shields.io/badge/Security-A-2e7d32)](https://claudskills.com/skills/extended-statistics/#security)

Free. No spam. Unsubscribe in one click.

More Science & Research skills

Browse all Science & Research skills in the ClaudSkills registry, or explore these other picks from the same category:

Browse all Science & Research skills → Top 100 skills
Part of ClaudSkills — the open registry for Claude Skills & Claude Code Skills.  ·  What's New  ·  Install guide  ·  About  ·  llms.txt

Part of Acreator Store — Adam Lankamer's AI tools: PerfectStudio · Ucaption · UTagger · AutoXPoster · TestYourSkills · AutomationFlows · Au Naturel · Telegram @acreatorstore

Categories

Use cases

Popular tags

Learn

Site