query-writing
Writes and executes SQL queries from simple SELECTs to complex multi-table JOINs, aggregations, and subqueries. Use when the user asks to query a database, write SQL, run a SELECT statement, retrieve data, filter records, or generate reports from database tables.
- Installs
- 1.3K
- Last 24h
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- Trending rank
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- Security
- Not audited
Install
Works with every agent the skills CLI supports.
npx skills add https://github.com/langchain-ai/deepagents --skill query-writing- 01
Install
Run the command in your project. The CLI asks which agents to install for.
- 02
Describe the task
Ask your agent for something this skill covers. It loads query-writing automatically when relevant.
- 03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.
SKILL.md
The instructions your agent reads when the skill is triggered.
Query Writing Skill
Workflow for Simple Queries
For straightforward questions about a single table:
- Identify the table - Which table has the data?
- Get the schema - Use
sql_db_schemato see columns - Write the query - SELECT relevant columns with WHERE/LIMIT/ORDER BY
- Execute - Run with
sql_db_query - Format answer - Present results clearly
Workflow for Complex Queries
For questions requiring multiple tables:
1. Plan Your Approach
Use write_todos to break down the task:
- Identify all tables needed
- Map relationships (foreign keys)
- Plan JOIN structure
- Determine aggregations
2. Examine Schemas
Use sql_db_schema for EACH table to find join columns and needed fields.
3. Construct Query
- SELECT - Columns and aggregates
- FROM/JOIN - Connect tables on FK = PK
- WHERE - Filters before aggregation
- GROUP BY - All non-aggregate columns
- ORDER BY - Sort meaningfully
- LIMIT - Default 5 rows
4. Validate and Execute
Check all JOINs have conditions, GROUP BY is correct, then run query.
Example: Revenue by Country
SELECT
c.Country,
ROUND(SUM(i.Total), 2) as TotalRevenue
FROM Invoice i
INNER JOIN Customer c ON i.CustomerId = c.CustomerId
GROUP BY c.Country
ORDER BY TotalRevenue DESC
LIMIT 5;
Error Recovery
If a query fails or returns unexpected results:
- Empty results — Verify column names and WHERE conditions against the schema; check for case sensitivity or NULL values
- Syntax error — Re-examine JOINs, GROUP BY completeness, and alias references
- Timeout — Add stricter WHERE filters or LIMIT to reduce result set, then refine
Quality Guidelines
- Query only relevant columns (not SELECT *)
- Always apply LIMIT (5 default)
- Use table aliases for clarity
- For complex queries: use write_todos to plan
- Never use DML statements (INSERT, UPDATE, DELETE, DROP)
FAQ
What does the query-writing skill do?
Writes and executes SQL queries from simple SELECTs to complex multi-table JOINs, aggregations, and subqueries. Use when the user asks to query a database, write SQL, run a SELECT statement, retrieve data, filter records, or generate reports from database tables.
How do I install query-writing?
Run npx skills add https://github.com/langchain-ai/deepagents --skill query-writing in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/query-writing/ (personal) or .claude/skills/query-writing/ (project).
Which AI agents can use query-writing?
Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.
Is query-writing safe to install?
No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.
Who maintains query-writing?
It is published by langchain-ai in langchain-ai/deepagents, and it is an official skill from the maker of the technology it covers. It has 1,268 recorded installs.
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