ETL vs ELT
The ETL-vs-ELT choice shapes your entire pipeline architecture and tooling decisions.
Learn it
Learn that ETL transforms data before loading (on a separate engine) while ELT loads raw data first and transforms inside the warehouse. Understand why cloud warehouses made ELT dominant, and where legacy/regulated ETL still fits. Map each pattern to cost, scalability, and freshness trade-offs.
By the end you’ll be able to
- Explain the order-of-operations difference between ETL and ELT
- Choose the right pattern for a given source, scale, and warehouse
Free resources
Practice
Write a one-page decision note: for two scenarios (small on-prem finance data; large cloud clickstream), pick ETL or ELT and justify it.
Build it — your output
A short decision memo recommending ETL or ELT for two contrasting scenarios with reasoning.
Prove it — check yourself
You’re ready to move on when you can honestly say yes to each:
- Can you state where transformation runs in ETL vs ELT?
- Can you name two reasons ELT became popular with cloud warehouses?
- Can you give one case where ETL is still the better choice?
Do it with AI
Use a free AI tool as your tutor and pair-programmer. Copy a prompt below into Claude, ChatGPT, or Gemini (for building, try Cursor or Copilot).
The habit: Try it yourself first — a little struggle is where the learning actually happens. Then ask for a hint before the answer — never copy blindly.
- Understand itClaude / ChatGPT / Gemini
I'm a beginner learning "ETL vs ELT". Explain it in simple terms with a real-world analogy, then ask me ONE question to check my understanding — don't reveal the answer.
- PracticeClaude / ChatGPT / Gemini
Give me 3 short practice problems on "ETL vs ELT" (my goal: explain the order-of-operations difference between etl and elt), from easy to hard. Don't include the solutions yet — I'll try them first, then ask you to check.
- Get unstuckClaude / ChatGPT / Gemini
I'm stuck on this exercise about "ETL vs ELT": [paste your attempt here]. Give me ONE small hint to move forward — do NOT give me the full solution.
- Build & reviewCursor / Copilot
Here is my work for a "ETL vs ELT" task: [paste your code or answer]. Review it: point out what's wrong and WHY, and suggest improvements — but let me make the fixes myself.
- Prove itClaude / ChatGPT / Gemini
Quiz me on "ETL vs ELT". Ask me 5 questions one at a time, wait for my answer each time, then tell me if I'm right and briefly why.