SQL Query Builder

Write a SQL query based on my plain English description.

**What I need the query to do:**
[Describe what you want to retrieve, calculate, or update in plain English]

**My database schema:**
[Paste your table definitions, or describe the tables and their columns. e.g.:
- users (id, name, email, created_at, plan_type)
- orders (id, user_id, amount, status, created_at)
- products (id, name, category, price)]

**Database type:**
[PostgreSQL / MySQL / SQLite / BigQuery / Snowflake / SQL Server / other]

**Any filters, conditions, or constraints:**
[e.g. only last 30 days, only paying customers, exclude cancelled orders, group by month]

**Output format I need:**
[e.g. one row per user, aggregated totals, ranked list, percentage breakdown]

Write the SQL query with:
1. The complete, runnable query
2. A plain English walkthrough of what each clause does
3. Any indexes or columns that should exist for this query to perform well
4. Edge cases to watch for (e.g. NULLs, duplicates, empty joins)
5. An alternative approach if there's a simpler or faster way to get the same result