SQL Inner Join | Dataford Interview Questions

Wolfspeed's manufacturing systems track production lots for silicon carbide wafer processing. Write a PostgreSQL query that returns only released lots from the Epi process area.

Requirements

Return the lot number, process area, lot status, and wafer count.
Include only rows where process_area is Epi and lot_status is Released.
Sort the results by lot_number in ascending order.

Schema

production_lots

Column	Type	Description
lot_idPK	INTEGER	Unique production lot identifier
lot_number	VARCHAR(20)	Manufacturing lot number
process_area	VARCHAR(30)	Manufacturing process area
lot_status	VARCHAR(20)	Current lot status
wafer_count	INTEGER	Number of wafers in the lot

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Problem

Wolfspeed's manufacturing systems track production lots for silicon carbide wafer processing. Write a PostgreSQL query that returns only released lots from the Epi process area.

Requirements

Return the lot number, process area, lot status, and wafer count.
Include only rows where process_area is Epi and lot_status is Released.
Sort the results by lot_number in ascending order.

Schema

production_lots

Column	Type	Description
lot_idPK	INTEGER	Unique production lot identifier
lot_number	VARCHAR(20)	Manufacturing lot number
process_area	VARCHAR(30)	Manufacturing process area
lot_status	VARCHAR(20)	Current lot status
wafer_count	INTEGER	Number of wafers in the lot

Your question is SQL Inner Join. 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.