SQL EXPLAIN plan explainer

Ingredients

• Raw EXPLAIN output from PostgreSQL, MySQL, or SQLite
• Optional: table row counts and index definitions
• Optional: slow-query-log threshold in ms

What you get

• Node-by-node translation of scan types, join strategies, and sort operations
• Cost breakdown: startup cost, total cost, estimated rows vs actual
• Bottleneck flagging: sequential scans on large tables, missing indexes, hash-join spills
• Actionable rewrite suggestions with before/after snippets

Example prompt

EXPLAIN ANALYZE SELECT o.id, c.name
FROM orders o
JOIN customers c ON o.customer_id = c.id
WHERE o.created_at > '2025-01-01'
ORDER BY o.total DESC LIMIT 50;

-- Table: orders (2.3M rows, indexed on customer_id, created_at)
-- Table: customers (180K rows, PK id)