# Indexes — MySQL

Source: https://www.geekswithgeeks.com/en/mysql/sql-indexes

> Speed up lookups on large tables.

## What an index does

An **index** is a sorted lookup structure on a column — it lets MySQL find matching rows without scanning the whole table.

## Like a book's index

Just like a book's index lets you jump to a page instead of reading cover to cover, a database index skips straight to matching rows.

## Creating an index

Index columns you frequently filter or join on.

```sql
CREATE INDEX idx_orders_customer
ON orders (customer_id);
```