5 SQL mistakes I made as a junior Business Analyst

I wish someone had caught these earlier. If you’re early in your BA career, this one’s for you. Nobody starts out writing clean SQL. I definitely didn’t. When I was a junior BA, I spent a lot of time producing queries that technically worked — but were slow, fragile, or just plain wrong in ways I didn’t catch until a stakeholder asked an awkward question in a review meeting. Here are the five mistakes I made most often, and what I’d tell my past self to do instead.

The Real Lesson

1. SQL skill isn’t about writing the most complex query. It’s about writing the most trustworthy one.
2. Every mistake on this list came from moving too fast. Slowing down to validate saves hours of rework later.
3. The best BAs I know aren’t the best coders — they’re the ones whose numbers stakeholders never have to question.