Skills sql-expert

🗃️

sql-expert

Name: sql-expert
Author: hmohamed01

Safe ⚙️ External commands🌐 Network access

Write and optimize T-SQL queries for SQL Server

Also available from: AutumnsGrove

Get expert help writing complex T-SQL queries, stored procedures, and performance optimizations for Microsoft SQL Server. Covers advanced patterns like CTEs, window functions, PIVOT, and MERGE statements.

Supports: Claude Codex Code(CC)

📊 71 Adequate

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Test it

Using "sql-expert". Write a recursive CTE to traverse an organizational hierarchy where each employee has a manager_id pointing to another employee

Expected outcome:

WITH RECURSIVE hierarchy AS (
-- Anchor: top-level employees (no manager)
SELECT id, name, manager_id, 0 AS level
FROM employees WHERE manager_id IS NULL
UNION ALL
-- Recursive: employees reporting to current level
SELECT e.id, e.name, e.manager_id, h.level + 1
FROM employees e
INNER JOIN hierarchy h ON e.manager_id = h.id
)
SELECT * FROM hierarchy OPTION (MAXRECURSION 100)

Using "sql-expert". How do I implement keyset pagination for better performance on large tables?

Expected outcome:

Keyset (seek method) pagination is more efficient than OFFSET for large datasets:
CREATE PROCEDURE GetProductsPage
@LastProductId INT,
@PageSize INT = 20
AS
BEGIN
SELECT TOP (@PageSize) * FROM Products
WHERE ProductId > @LastProductId
ORDER BY ProductId;
END
Benefits: consistent performance at any page, works with real-time data

Security Audit

Safe

v3 • 1/17/2026

This is a documentation-only skill containing markdown files with T-SQL code examples. All 265 static findings are FALSE_POSITIVES. The analyzer incorrectly flags markdown syntax (triple backticks for code blocks) as shell commands, security education content as vulnerabilities, and SQL Server features like encryption as weak crypto. No executable code, network access, or file system operations exist.

Files scanned

3,072

Lines analyzed

findings

Total audits

Risk Factors

⚙️ External commands (152)

🌐 Network access (2)

references/patterns.md:8 skill-report.json:6

Audited by: claude View Audit History →

Quality Score

Architecture

100

Maintainability

Content

Community

100

Security

Spec Compliance

What You Can Build

Write complex T-SQL queries

Create queries with advanced patterns like recursive CTEs, running totals, and gap detection

Optimize slow queries

Analyze query patterns and execution plans to identify and fix performance bottlenecks

Build secure stored procedures

Implement parameterized queries, proper error handling, and transaction management patterns

Try These Prompts

Basic query help

Write a T-SQL query to select all orders from last month with their customer names, joining the Orders and Customers tables

Advanced pattern

Create a query using window functions to show each product with its sales, running total, and rank within category

Performance tuning

This query takes 30 seconds to run on a table with 10 million rows. Suggest optimizations including index changes and query rewrite: SELECT * FROM transactions WHERE YEAR(date) = 2024

Security patterns

Show me how to safely build a dynamic WHERE clause that accepts user input for filtering, preventing SQL injection while allowing optional filters

Best Practices

Always use parameterized queries with sp_executesql instead of string concatenation to prevent SQL injection
Write SARGable queries by avoiding functions on indexed columns in WHERE clauses
Handle NULLs explicitly using IS NULL, ISNULL(), or COALESCE rather than relying on defaults

Avoid

Using SELECT * in production queries - explicitly list columns to improve performance and avoid schema binding issues
Calling functions on indexed columns in WHERE clauses (e.g., WHERE YEAR(date) = 2024) which prevents index usage
Not validating or white-listing dynamic object names in dynamic SQL, even when using sp_executesql

Frequently Asked Questions

What versions of SQL Server are supported?

The skill covers features from SQL Server 2012 through 2022, with version-specific notes for features like STRING_AGG (2017+) and GENERATE_SERIES (2022+).

Can this skill help with database migration?

Yes, the skill can help translate patterns between SQL Server and other databases, optimize migration queries, and handle data type conversions.

Does the skill provide execution plan analysis?

Yes, describe your query and execution plan operators (Table Scan, Key Lookup, Hash Match) for specific optimization recommendations.

How do I handle dynamic sorting safely?

Validate sort columns against a whitelist, then use QUOTENAME() for the column name. Never concatenate user input directly into ORDER BY clauses.

What error handling patterns are recommended?

Use TRY...CATCH blocks with proper transaction rollback. Check @@TRANCOUNT before rolling back and use THROW to re-raise exceptions.

Can this help with JSON and XML processing?

Yes, the skill covers OPENJSON, FOR JSON, and XML methods for parsing and generating structured data in SQL Server 2016+.

Developer Details

Author

hmohamed01

License

MIT

Repository

https://github.com/hmohamed01/SQL-Expert/tree/main/sql-expert

Ref

main

File structure

📁 references/

📄 data-types.md

📄 patterns.md

📄 performance.md

📄 security.md

📄 transactions.md

📄 evaluation.json

📄 SKILL.md