Analyze Decision Impact by Region | Dataford Interview Questions

You are given transaction, decision, and client data from an investment operations workflow. Write a PostgreSQL query that helps you decide whether a process change improved outcomes: for each region, return the number of decisions made, the number of successful outcomes, and the success rate for decisions made in Q2 2024. Only include regions with at least 2 decisions, and sort by success rate descending, then region ascending.

Output details

Return columns in this order: region, decisions_made, successful_outcomes, success_rate.
Filter dates inclusively from DATE '2024-04-01' through exclusively before DATE '2024-07-01'.
Round success_rate to 2 decimal places.
Treat NULL or non-success outcomes as unsuccessful.
Count qualifying rows without deduplication.

Schema

decisions

Column	Type	Description
decision_idPK	INT	Primary key for each decision record
client_id	INT	Client associated with the decision
decision_date	DATE	Date the decision was made
decision_type	VARCHAR(50)	Type of decision

decision_outcomes

Column	Type	Description
decision_id	INT	Foreign key to decisions.decision_id
outcome_status	VARCHAR(20)	Outcome status such as success or failure
resolved_at	TIMESTAMP	When the outcome was recorded

clients

Column	Type	Description
client_idPK	INT	Primary key for each client
region	VARCHAR(50)	Client region
account_name	VARCHAR(100)	Client account name

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