NULL vs Empty String: Why "No Data" Isn't Always the Same Thing

If you've worked with databases for more than a week, you've probably hit this moment: a text field has no data, and you have to decide: do I leave it NULL , or do I set it to an empty string '' ? It looks like a trivial choice. It isn't. Pick wrong (or pick inconsistently) and you'll spend years explaining weird bugs in your reports. Let's break down what each one actually means, why most…