## Table of content

- Introduction
- Basic Percentages in SQL
- Calculating Percentage Change
- Finding Percentage of Total
- Working with Distinct Values
- Analyzing Percentage Differences
- Applying Percentages to Real-Life Scenarios
- Conclusion

### Introduction

Hey there, my fellow SQL enthusiasts! Are you tired of manually calculating percentages in your SQL queries? Let me tell you, I used to be in the same boat. But then I discovered a nifty little trick that made my life so much easier. Are you ready for it? It's all about using the power of SQL to do the calculations for you! How amazing would it be to never have to whip out your calculator again? Trust me, once you learn how to do this, you'll be thanking yourself. So, let's dive right in and discover the secret to calculating percentages in SQL with these easy-to-follow code examples.

### Basic Percentages in SQL

So, you want to know how to calculate ? No problemo! It's actually super easy and nifty.

First of all, you need to know the formula for calculating percentages. It's simple: (part/whole) x 100. So, let's say you want to calculate the percentage of customers who bought a particular product. The "part" would be the number of customers who bought the product, and the "whole" would be the total number of customers. Got it? Great!

Now, let's dive into some SQL code. Suppose you have a table called "orders" that contains information about customer orders. One of the columns in this table is "product_type", which tells you the type of product that was ordered. To calculate the percentage of orders that were for a specific product type, you can use the following code:

```
SELECT COUNT(*) * 100.0 / (SELECT COUNT(*) FROM orders) AS percentage
FROM orders
WHERE product_type = 'specific_product_type';
```

Let's break this down. The first line of the code selects the count of all orders for the specific product type and then multiplies the result by 100.0 (note the decimal point!). The second line of the code divides the result by the total number of orders in the table. This gives you the percentage of orders that were for the specific product type.

See, how amazingd it be! Now, go ahead and try it out for yourself. Calculate some percentages in SQL and impress your boss or colleagues with your newfound knowledge. You got this!

### Calculating Percentage Change

in SQL is a nifty trick that can come in handy when you're dealing with a ton of data. With just a few lines of code, you can figure out how much something has increased or decreased over time. It's not the most complicated piece of SQL wizardry out there, but it's definitely up there in terms of usefulness.

So, how do you calculate percentage change in SQL? Well, it's pretty simple. Let's say you have a table with sales data for the past three years. You want to figure out how much sales have increased or decreased from year to year. Here's how you can do it:

First, you'll need to create a subquery to get the total sales for each year. This is done by using the SUM function and grouping the data by year. Once you have that information, you can use the LAG function to get the sales from the previous year. Finally, you can calculate the percentage change by dividing the difference between this year's sales and last year's sales by last year's sales and multiplying by 100.

Voila! You now have the percentage change in sales from year to year. How amazing is that? With a little bit of SQL knowledge and some nifty functions, you can make sense of your data in no time. So go ahead, give it a try!