WWorkTools
SQL · PRACTICAL GUIDE

SQL Last 30 Days Filter

Build rolling date filters that update automatically.

Practice SQLLearning path

What this solves

Show transactions from the most recent 30 days. This pattern is useful when the business question is clear but a generic tutorial is too abstract.

The rule

Use the date function appropriate to your database and compare against a calculated boundary.

SELECT * FROM Transactions
WHERE EventDate >= DATEADD(day,-30,CURRENT_TIMESTAMP);

Real-work checklist

  1. Define the business key and expected grain before writing the formula, query or markup.
  2. Test the pattern on a small known sample where you can verify the answer manually.
  3. Check missing values, duplicates and data types before trusting a large result.
  4. Scale to the real file or database only after the logic is proven.

Common mistake

Date syntax differs between SQL Server, PostgreSQL, MySQL and SQLite.

Try it next

PracticeChange the example and verify the result.Use a toolMove from a small example to real work.Related contentFind guides, errors and scenarios on this topic.