Charles J

Data Analyst Intern (SQL)

Windle • Full-time

Jan 2023 - Aug 2023 • 7 mos

Wrote complex SQL queries across PostgreSQL databases to extract, clean, and analyse business datasets for weekly management reporting. Built and maintained ETL pipelines that pulled data from multiple source systems into a central data warehouse, reducing manual data preparation time by 35%. Created data quality checks using SQL (NULL validation, duplicate detection, row count reconciliation) to ensure pipeline integrity across all reporting tables. Collaborated with senior analysts to design dashboard-ready summary views and aggregation tables consumed by Power BI reports. Documented SQL query logic and pipeline steps, improving team knowledge sharing and onboarding efficiency.