Second Highest Trade Volume Query | Dataford Interview Questions

Your question is Second Highest Trade Volume Query. Start with the requirements and the two tables on the right.

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Problem

Apollo Global Management's investment reporting team needs to compare instrument activity across asset classes. Write a PostgreSQL query that finds the second-highest trade volume for each asset class during February 2025.

Requirements

Filter trades to the half-open date range from 2025-02-01 through, but not including, 2025-03-01.
Calculate total trade volume as the sum of quantity for each instrument.
Rank instruments within each asset class by total volume in descending order.
Return every instrument tied for second place, along with its asset class and total volume.
Exclude instruments whose asset class is null, and order the final results by asset class and instrument ID.

Schema

instruments

Column	Type	Description
instrument_idPK	INT	Unique instrument identifier
instrument_name	VARCHAR(100)	Instrument or fund name
asset_class	VARCHAR(50)	Investment asset class

trades

Column	Type	Description
trade_idPK	INT	Unique trade identifier
instrument_id	INT	Instrument associated with the trade
trade_timestamp	TIMESTAMP	Trade execution timestamp
quantity	NUMERIC(18,2)	Number of units traded