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If you’ve ever seen your backend API take forever to load — like 10 seconds just to show some data — there’s a high chance the problem isn’t your code… it’s your SQL.

But don’t worry — this isn’t another boring “use indexes” article. We’ll go step-by-step, in simple language, so even if you’re not a database expert, you’ll get it immediately.

1. Don’t Bring Everything — Take Only What You Need

Imagine you’re in a restaurant. You say:

“Bring me everything on the menu.

The waiter takes 30 minutes.

But if you say:

“Just a burger and fries.”

You get it in 5 minutes.

That’s exactly what happens in SQL. If you write:

SELECT * FROM orders;

You’re bringing every column.

Instead:

SELECT id, customer_name, total_price FROM orders;

Only bring what your app actually needs — it’s faster and lighter.