DATE_ADD()

Concepts covered: sqlDateAdd

Adding Time Intervals Adding Days The most common use case is adding days to calculate due dates or deadlines: Different Time Units Subtracting Time Negative Amounts Use negative amounts to subtract time and look backward: Negative values move backward in time. This is essential for historical analysis, comparing year-over-year metrics, and calculating retention windows. Best Practices When to Use DATE_ADD() Here are the most common scenarios where date arithmetic is needed.

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This section is part of the Dates: Beginner 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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