How to round an average to 2 decimal places in PostgreSQL?

How to Round an Average to 2 Decimal Places in PostgreSQL 🧮

Are you stuck on how to round an average to two decimal places in PostgreSQL? You're not alone! Many developers face this issue when working with PostgreSQL and Ruby gem 'sequel'. But fret not, we’ve got you covered! In this blog post, we'll address this common problem and provide you with easy solutions to help you get the desired result. So let's dive right in! 💻🚀

The Error Message: 🚫

Let's start by taking a look at the error message you're encountering:

PG::Error: ERROR: function round(double precision, integer) does not exist (Sequel::DatabaseError)

This error occurs when you use the ROUND function with a decimal precision argument. The ROUND function in PostgreSQL expects a single argument of type numeric or double precision as the input, but you're passing an integer as the rounding precision.

The Solution: ✅

To round an average to two decimal places, you need to specify the precision as a decimal number instead of an integer. Here's how you can achieve that:

SELECT ROUND(AVG(some_column)::numeric, 2)
FROM table;

By casting AVG(some_column) as numeric, you ensure that the rounding precision argument accepts decimal values. In this case, we specify 2 as the decimal precision, rounding the average to two decimal places.

The Corrected Code: 👨‍💻

Let's take a look at the corrected code:

SELECT ROUND(AVG(some_column)::numeric, 2)
FROM table;

Now, you're ready to round your average to two decimal places without any error!

Pro Tip: 💡

If you want to display the rounded value with the appropriate number of decimal places, you can use the CAST function. Here's an example:

SELECT CAST(ROUND(AVG(some_column)::numeric, 2) AS decimal(10,2)) AS average_value
FROM table;

In the above code, CAST is used to explicitly specify the data type as decimal(10,2), which means a total of 10 digits with 2 decimal places.

Call-to-Action: 📢

Congratulations! You've learned how to round an average to two decimal places in PostgreSQL. Now it's time to apply this knowledge in your own projects and share it with your fellow developers. If you have any questions or feedback, feel free to leave a comment below. Happy coding! 💪😄

Remember, sharing is caring! Don't forget to share this blog post with your friends and colleagues who might find it helpful. 🤗🔗