SQL to Business Logic Translator

When to use

• A stakeholder asks "what exactly does this query calculate?"
• Documenting a query library or a dbt model for non-technical readers
• Reviewing a query for correctness by comparing its logic to the business requirement
• Onboarding new analysts to existing SQL patterns
• Translating legacy undocumented queries before refactoring

Process

1. Receive the query and context — obtain the SQL and the business question it answers. Also collect any schema notes (what the key tables and columns represent in business terms).
2. Translate the FROM/JOIN structure — describe in plain language which data sources are combined and what type of join is used (inner keeps only matches; left keeps all rows from the left side). Note if the join type seems inconsistent with the stated purpose.
3. Translate WHERE filters — list each filter condition as a business rule in plain language (e.g., status = 'completed' → "only includes orders that have been paid and fulfilled").
4. Explain GROUP BY and aggregations — describe what each aggregation computes and at what grain. Use scripts/sql_explainer.py to automate a first-pass structural parse.
5. Summarise output columns — for each output column, state its business meaning and any edge cases (nulls, rounding, currency units).
6. Flag issues and write validation questions — identify potential problems (implicit null propagation, unexpected fan-out, hardcoded dates). Generate 3–5 questions the query author should confirm. Use assets/query_documentation_template.md to record the full translation.

Inputs the skill needs

• The complete SQL query (SELECT through ORDER BY)
• The business question the query is intended to answer
• Table and column descriptions (or a data catalog entry)
• Any business rules for key status values, date handling, or currency
• The intended output: who reads the result and for what decision

Output

• scripts/sql_explainer.py — parses a SQL query and generates a structured plain-language explanation
• assets/query_documentation_template.md — completed translation covering purpose, step-by-step logic, output columns, business rules, and validation questions
• Optionally: a flowchart representation of the query logic