GROUP BY vs PARTITION BY | Dataford Interview Questions

In SQL, what is the difference between GROUP BY and PARTITION BY?

Explain the distinction and demonstrate both behaviors using the supplied PostgreSQL table. Return one row per venue and trading date, including daily totals and the venue total repeated for each date.

Output

Columns: venue, trade_date, daily_notional, daily_trade_count, and venue_total_notional.
Include every venue and date combination present in the data.
Order by venue ascending with NULL venues last, then trade_date ascending.

Schema

trades

Column	Type	Description
trade_idPK	INT	Unique trade identifier
venue	VARCHAR(50)	Trading venue associated with the trade
trade_date	DATE	Calendar date on which the trade occurred
notional	NUMERIC(12,2)	Trade notional amount

Your question is GROUP BY vs PARTITION BY. Start with the requirements and the one table in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem

In SQL, what is the difference between GROUP BY and PARTITION BY?

Output

Columns: venue, trade_date, daily_notional, daily_trade_count, and venue_total_notional.
Include every venue and date combination present in the data.
Order by venue ascending with NULL venues last, then trade_date ascending.

Schema

trades

Column	Type	Description
trade_idPK	INT	Unique trade identifier
venue	VARCHAR(50)	Trading venue associated with the trade
trade_date	DATE	Calendar date on which the trade occurred
notional	NUMERIC(12,2)	Trade notional amount

Your question is GROUP BY vs PARTITION BY. Start with the requirements and the one table in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.