Why Raw SQL when needed in Ruby on Rails? - Purpose & Use Cases

The Big Idea

What if you could speak directly to your database and get exactly what you want, no limits?

The Scenario

Imagine you need to get a complex report from your database, but your usual Rails queries just can't express it easily.

The Problem

Trying to build this report with only Rails query methods can be slow, confusing, and sometimes impossible, leading to messy code and poor performance.

The Solution

Using raw SQL lets you write exactly the database commands you need, making complex queries clear, fast, and reliable.

Before vs After

✗ Before

User.where("age > ?", 30).joins(:orders).group('users.id').having('count(orders.id) > 5')

✓ After

ActiveRecord::Base.connection.execute("SELECT users.*, COUNT(orders.id) FROM users JOIN orders ON orders.user_id = users.id WHERE users.age > 30 GROUP BY users.id HAVING COUNT(orders.id) > 5")

What It Enables

You can unlock powerful database features and optimize performance beyond what Rails queries allow.

Real Life Example

A sales dashboard needing a fast summary of customers with many orders in the last month, using a complex SQL query for speed.

Key Takeaways

Rails queries are great but sometimes limited.

Raw SQL gives you full control for complex needs.

It helps write faster, clearer, and more powerful database commands.