sql-query-explainer

sql-query-explainer is a skill for Claude Code from cnfeat/top-pm-skills. It costs 100 tokens per session (1,058 once invoked), scanned A, original, MIT.

A plain-language guide for understanding, writing, improving, or documenting SQL queries. SQL is the language commonly used to retrieve and analyse data in databases.

In plain words
What is it for?
Explaining query logic, optimising slow queries, writing new queries, and documenting data outputs.
Why use it?
It helps explain what a query returns, find possible performance problems, or turn a business request into SQL.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the pm-data plugin — 6 skills shipped together

Good fit Explaining query logic, optimising slow queries, writing new queries, and documenting data outputs.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/cnfeat/top-pm-skills/sql-query-explainer
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add cnfeat/top-pm-skills --skill sql-query-explainer
Clone the repo
git clone --depth 1 https://github.com/cnfeat/top-pm-skills

Made for: Claude Code.

Or install pm-data, the plugin that ships this one along with the rest of its 6 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for sql-query-explainer

README.md
[![agentmods](https://agentmods.dev/badge/skills/cnfeat/top-pm-skills/sql-query-explainer.svg)](https://agentmods.dev/skills/cnfeat/top-pm-skills/sql-query-explainer)
Your own site
<a href="https://agentmods.dev/skills/cnfeat/top-pm-skills/sql-query-explainer"><img src="https://agentmods.dev/badge/skills/cnfeat/top-pm-skills/sql-query-explainer.svg" alt="Measured on agentmods" height="20"></a>
Per session 100 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,058 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00100 $0.01058
Opus 5 $0.00050 $0.00529
Sonnet 5 $0.00020 $0.00212
Haiku 4.5 $0.00010 $0.00106

Measured 4d ago against content hash 374ed34aacb5, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

sql-query-explainer scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

参考skill/pm-claude-skills-main/pm-claude-skills-main/plugins/pm-data/skills/sql-query-explainer/SKILL.md · 144 lines

How it starts

The opening of the file, as written. The whole thing — 144 lines — stays where its author put it; the contents beside it link to each section on GitHub.

SQL Query Explainer Skill

This skill explains SQL queries in plain language, identifies optimisation opportunities, and helps communicate data logic to non-technical stakeholders. It also writes and documents new queries from natural language descriptions.

Modes

Detect which mode the user needs based on their request:

  1. Explain — Translate existing SQL into plain English
  2. Optimise — Review SQL for performance issues and suggest improvements
  3. Write — Generate SQL from a natural language description
  4. Document — Produce a data dictionary or query documentation

Mode 1: Explain

When given a SQL query, produce:

Plain English Summary

[1–3 sentences. What does this query do? What data does it return? Write as if explaining to a business analyst, not a developer.]

Step-by-Step Walkthrough

Break the query into logical sections. For each section:

  • Quote the SQL clause
  • Explain what it does in plain English
  • Flag any complexity (e.g. window functions, subqueries, CTEs)

What the Result Looks Like

[Describe the shape of the output: "Returns one row per user, with columns for X, Y, Z. Ordered by [field] descending."]

Potential Issues to Flag

  • [Gotchas, edge cases, or implicit assumptions in this query]
  • [e.g. "This will include NULLs in the user_id column if the LEFT JOIN finds no match"]

Mode 2: Optimise

When asked to optimise a query, produce:

Performance Assessment

Rate overall: 🟢 Well-optimised / 🟡 Some improvements possible / 🔴 Significant issues

Issues Found

For each issue:

Issue [N]: [Short name, e.g. "Missing index on join column"]

  • What it is: [Plain explanation]
  • Why it matters: [Performance impact — e.g. "Full table scan on a 10M row table"]
  • Fix:
-- Before
[original snippet]

-- After
[improved snippet]
  • Expected improvement: [Estimate if possible]

Optimisation Checklist

  • SELECT * used? (Replace with specific columns)
  • Implicit type conversions on JOIN/WHERE columns?
  • Missing indexes on JOIN or WHERE columns?
  • N+1 patterns (queries inside loops)?
  • DISTINCT used where GROUP BY would be faster?
  • Window functions used where a subquery would be clearer/faster?
  • CTEs re-used or materialised unnecessarily?
  • Large IN() lists that could use a JOIN instead?

Read the full file on GitHub · 144 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 4d ago First seen · 144 lines · 100 tokens per session scan A 374ed34aacb5

Subscribe to this mod's changes

sql-query-explainer is a skill published in the GitHub repository cnfeat/top-pm-skills (48 stars, last pushed 2mo ago), licensed MIT. It adds 100 tokens to every session and 1,058 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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