sql-style-mlisted

# SQL Style Two sections: **General SQL rules** (any dialect) and **Snowflake-specific rules** (apply when the target is Snowflake). Some general rules are marked **(aspirational)** — they pull new code toward the standard; legacy code is what it is. Real-world reference: a well-sectioned feature-engineering model (numbered sections, source CTEs, progressive JOIN CTEs) is the canonical example of these conventions in action — especially the sectioning and progressive-JOIN patterns below. --- ## Section 1 — General SQL rules ### Layout & syntax - **Keywords UPPERCASE** — `SELECT`, `FROM`, `WHERE`, `INNER JOIN`, `QUALIFY`, etc. (needed for SQL syntax highlighting inside Python string literals). - **Identifiers lower_snake_case** — `user_id`, `order_date`. No `.` in names. No leading digits. - **Trailing commas, not leading.** - **4-space indent** inside SELECT lists, CTE bodies, subqueries, and `ON` continuation lines. - **Spaces around operators** — `price > 100`, `a.id = b.user_id`. - **Parentheses for complex logic** — group conditions in WHERE / CASE for clarity. - **Single quotes for string literals** — `'active'`, `'2026-01-01'`. ### Aliases - **Always `AS`** for aliases — `users AS usr`, `total AS order_total` *(aspirational)*. - **Descriptive initials** — `usr`, `ord`, `prd`, `evt` — **never single letters** (`u`, `o`, `a`). - **Cap at 3 letters**; extend to 4 only when 3 would collide (e.g., `payments` vs `payouts` → `pmt` / `pyt`). - **Same length per CTE/bloc