name: mysql-best-practices description: MySQL performance optimization and best practices. Use this skill when writing, reviewing, or optimizing MySQL queries, schema designs, or database configurations. license: MIT metadata: author: mysql-community version: "1.0.0" organization: MySQL Community date: January 2026 abstract: Comprehensive MySQL performance optimization guide for developers. Contains performance rules across 8 categories, prioritized by impact from critical (query performance, connection management) to incremental (advanced features). Each rule includes detailed explanations, incorrect vs. correct SQL examples, query plan analysis, and specific performance metrics to guide automated optimization and code generation.

MySQL Best Practices

Comprehensive performance optimization guide for MySQL, adapted from PostgreSQL best practices. Contains rules across 8 categories, prioritized by impact to guide automated query optimization and schema design.

When to Apply

Reference these guidelines when:

Writing SQL queries or designing schemas
Implementing indexes or query optimization
Reviewing database performance issues
Configuring connection pooling or scaling
Optimizing for MySQL-specific features
Working with MySQL security features

Rule Categories by Priority

Priority	Category	Impact	Prefix
1	Query Performance	CRITICAL	`query-`
2	Connection Management	CRITICAL	`conn-`
3	Security	CRITICAL	`security-`
4	Schema Design	HIGH	`schema-`
5	Concurrency & Locking	MEDIUM-HIGH	`lock-`
6	Data Access Patterns	MEDIUM	`data-`
7	Monitoring & Diagnostics	LOW-MEDIUM	`monitor-`
8	Advanced Features	LOW	`advanced-`

How to Use

Read individual rule files for detailed explanations and SQL examples:

references/query-missing-indexes.md
references/schema-partial-indexes.md
references/_sections.md

Each rule file contains:

Brief explanation of why it matters
Incorrect SQL example with explanation
Correct SQL example with explanation
Optional EXPLAIN output or metrics
Additional context and references
MySQL-specific notes

Full Compiled Document

For the complete guide with all rules expanded: AGENTS.md

MySQL vs PostgreSQL Key Differences

This skill adapts PostgreSQL best practices to MySQL. Key differences:

JSON: MySQL uses JSON type (not JSONB), with JSON_EXTRACT(), JSON_CONTAINS() functions
Arrays: MySQL doesn't have native arrays; use JSON arrays or normalized tables
Full-Text Search: MySQL uses FULLTEXT indexes with MATCH() AGAINST() syntax
UUIDs: Use CHAR(36) or BINARY(16) instead of native UUID type
String Matching: Use LIKE (case-sensitive) or LIKE BINARY instead of ILIKE
Type Casting: Use CAST() function instead of :: operator
Window Functions: MySQL 8.0+ supports window functions (similar to PostgreSQL)

mysql-best-practices

SKILL.md