How do database engines manage to be so much faster at lookup / aggregation than your code?

Question

How do database engines manage to be so much faster at lookup / aggregation than your code?

In: 1

Answer 1

Depending on the DB implementation, it’s either because you’re accessing an in-memory database (saving I/O time) or indexing/caching. There are other possibilities (lower-level languages have way, way less overhead. Like, orders of magnitude less), but that will get you most of the way to explaining the difference.