SQL and Transformation Query Optimization | Dataford Interview Questions

How would you profile and optimize a slow-running SQL query or data transformation job impacting a core reporting dashboard? For the coding portion, implement the transformation that aggregates numeric values by key while preserving each key's first-seen order. Input is a list of [key, value] pairs, and output is a list of [key, total] pairs. For example, [['A', 2], ['B', 3], ['A', 4]] produces [['A', 6], ['B', 3]]. Keys are non-empty strings and values are integers.

Constraints

0 <= records.length <= 1000
Each record contains exactly two values: a non-empty string key and an integer value
Keys may repeat
The output must preserve the first-seen order of distinct keys

Function Signature

def aggregate_dashboard_rows(records):

Your question is SQL and Transformation Query Optimization. Start with the requirements 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

Constraints

0 <= records.length <= 1000
Each record contains exactly two values: a non-empty string key and an integer value
Keys may repeat
The output must preserve the first-seen order of distinct keys

Function Signature

def aggregate_dashboard_rows(records):

Your question is SQL and Transformation Query Optimization. Start with the requirements 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.