DATE_TRUNC()

Concepts covered: sqlDateTrunc

Truncating to Common Units Truncate to day, week, month, or year to group timestamps into buckets for aggregation. Grouping by Time Period Week Starts The truncated timestamp also works as an X-axis value in charts without additional formatting, making it ideal for time-series visualizations in BI tools.

About This Interactive Section

This section is part of the Dates: Advanced lesson on DataDriven, a free data engineering interview prep platform. Each section includes explanations, worked examples, and hands-on code challenges that execute in real time. SQL queries run against a live PostgreSQL database. Python runs in a sandboxed Docker container. Data modeling problems validate against interactive schema canvases. All content is framed around what data engineering interviewers actually test at companies like Meta, Google, Amazon, Netflix, Stripe, and Databricks.

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DataDriven combines four interview rounds (SQL, Python, Data Modeling, Pipeline Architecture) with adaptive difficulty and spaced repetition. Easy problems get harder as you improve. Weak concepts resurface until you master them. Your readiness score tracks progress across every topic interviewers test. Every lesson section ends with problems you solve by writing and running real code, not by picking multiple-choice answers.