SQL Report Builder

Write a SQL query (or set of queries) to produce the following report: [REPORT_DESCRIPTION]. Database: [DATABASE_TYPE — e.g., PostgreSQL, BigQuery, Snowflake, MySQL]. Available tables and their relevant columns: [TABLE_SCHEMA_DESCRIPTION]. Report requirements: (1) Metrics to calculate: [METRICS_LIST], (2) Dimensions to group by: [DIMENSIONS], (3) Filters to apply: [FILTERS — e.g., date range, active users only, specific regions], (4) Sort order: [SORT_ORDER], (5) Output format: [OUTPUT_FORMAT — e.g., one row per day per segment / one summary row per user]. Write the query with: (a) clear CTE (Common Table Expression) structure for readability — break complex logic into named steps, (b) inline comments on any non-obvious logic, (c) a note on expected query performance and any indexes that should exist for efficiency. After the query, provide a plain-English explanation of what each CTE or major section does. If any requirement is ambiguous or the schema appears to be missing data, flag it with a [QUESTION: ...] comment in the code.