PostgreSQL vs. MySQL: Which One Is Best?

The World Wide Web’s popularity has grown exponentially since it exploded on the scene in the 1990s, and the needs of its users have grown just as quickly. It is no longer commonplace for the best websites to be completely static, offering visitors no way to update, save, or access interactive data. The websites you use today need something more, and structured query language (SQL for short) relational databases give them those capabilities.

Put simply, a relational database stores and gives access to interconnected data, hence the term “relational.” Any time you log into Facebook, Twitter, Instagram, or any of your other favorite websites, you are likely interacting with an SQL database. This functionality is provided by a number of SQL servers available on the market. Two of the most popular are PostgreSQL vs. MySQL. 

If you’ve ever wondered which SQL server is the better choice, you’ve come to the right place: today’s guide will break down the differences between these two. Let’s get into it!

PostgreSQL vs. MySQL: Side-By-Side Comparison

PostgreSQL vs. MySQL: What’s the Difference?

Programmers have many options available to them when choosing the right SQL server software for their projects. In some cases, they might be limited to what their web host provides them. However, some hosts have both options available, so they need to make an informed choice as to which one is better for that particular application or website. So, let’s dive into what sets one apart from the other.

SQL Syntax

Though both PostgreSQL and MySQL use T-SQL, which stands for transact structured query language, there are slight differences in the types of queries they support. PostgreSQL is fully SQL-compliant, which means you can perform any type of SQL query and/or subquery you need. However, MySQL is not fully compliant.

The following queries can be done with a PostgreSQL server but not with MySQL:

LIMIT

This clause does exactly what you might think — it sets limits in your queries. It tells the server to only return a certain number of queries in the query you’re running.

Example use case:

You have a rather large database of candidates for a job in a web application for a nationwide tech staffing agency. When staffing for a remote position, you want to review the qualified applicants for the position. However, since those candidates can work from anywhere in the world, you’re working with a rather large pool of potential matches. Limiting your search by fifty candidates versus 1,000 would make your job much easier, and it would also save on time and resources on the web server.

PostgreSQL has the capability to run these large queries better than MySQL; however, it’s not always the best use of your server’s resources.

ALL

This command returns a boolean value (true or false) if all of the subquery values meet a particular condition.

Example use case:

You want to check to see if all students in a teacher’s class were passing the course. The query would run a check on every student in the class to see what their current grade was. If ALL the students had at least a D in the course, then the database would return true. Otherwise, it would return false. That false or true return value could tell a teacher or principal a lot about the class in question.

Though this is a powerful and useful query to run on your SQL database, when dealing with larger collections of data, it can be a resource hog, like these other complex queries and subqueries.

INTERSECT

This SQL clause only returns the rows from two SELECT statements where they INTERSECT.

Example use case:

You set up a database for a restaurant that recently had some issues with deliveries not arriving on time within the past month. The restaurant owner comes to you and wants to add capability in the admin area of their web application to show all the customers whose orders didn’t arrive within 45 minutes of ordering. The first SELECT statement would pull customers who ordered within the past 30 days, and the second would pull customers who received a late delivery. The INTERSECT clause would join those two SELECT statements together to return a list of customers who both ordered in the past 30 days and received a late delivery.

Though MySQL doesn’t support this feature of T-SQL syntax, it will have other, smarter ways to return the applicable data for this use case.

OUTERJOIN

The full OUTERJOIN returns records from two tables that either have values in the first table or the second table joined in one table. This is useful when you’re trying to make connections between the two tables where they exist.

Example use case:

You want to join a list of music students with a list of instruments available to rent for the duration of the semester, it would return them in one list. The OUTERJOIN would pair the instruments to the student who has checked them out. Any student who didn’t check out an instrument—or any instrument that wasn’t checked out—would display a NULL value.

Because this queries every single item in both tables, it can be time and resource intensive. This is likely the reason why MySQL doesn’t support it.

Data Types

One thing that differentiates PostgreSQL from MySQL is the number of data types available to use in your data tables. To compare, PostgreSQL has over forty data types to choose from, while MySQL has between thirty and forty available. There is also a distinction between the types of data types available.

One use case that can illustrate the differences between the functionality of the two is a content management system (CMS) that’s primarily used for blogging, like WordPress. MySQL has the following string data types available:

• CHAR
• VARCHAR
• TINYTEXT
• TEXT
• MEDIUMTEXT
• LONGTEXT
• ENUM
• SET

This variety of string data types makes MySQL a superior choice for blogs or other content-driven web applications because you are not limited to the available string data types available with PostgreSQL. MySQL’s string data types also give you choices depending on your length of text, which can also help you customize its performance by not using a data type that doesn’t suit your use case.

On the other hand, if you’re dealing with more complex data types, like you might with scientific or mathematical use cases, PostgreSQL is an ideal choice because it gives you better access to those complex data types. It goes beyond the basic integer and floating-point data you might only need with a basic database.

Performance

Not all SQL servers are created equal, and their performance will vary greatly, depending on what type of application you plan on building, what type of queries you need to execute, and the data types your application uses. In previous versions of these SQL servers, the differences in performance were much greater. However, there are still some situations where you might want to choose one over the other if you’re basing your decision on various performance factors.

In the table below, we’ve marked the SQL server option that provides the best performance in each scenario. 

Though this data favors PostgreSQL over MySQL, there will be other factors that determine performance further, such as hardware on the web server, operating systems, and experience of the developer who designed the database. All these factors must be considered before making your final choice.

PostgreSQL vs. MySQL: 5 Must-Know Facts

• If you learn how to build databases with PostgreSQL first, you will have a much easier time learning MySQL. Because PostgreSQL has more complex features than MySQL, many developers like to start by learning the more challenging SQL server option, so when they have future projects where MySQL is a better choice, they don’t have to spend a lot of time learning how to work with less complex data.
• When building applications that rely heavily on text or character data, MySQL is often the better choice because it performs better with text content and has more string data types available.
• PostgreSQL has more data types available than MySQL, so if you have a more complex need to manipulate different types of data, PostgreSQL might be a better choice for your project. 
• One thing that distinguishes MySQL from PostgreSQL is the server-side languages they support. PostgreSQL supports a few more languages than MySQL does. If having this type of flexibility is critical to the success of your next project, PostgreSQL would be a better choice for you.
• With all other things being equal, PostgreSQL performs better with more critical benchmarks than MySQL.

PostgreSQL vs. MySQL: Which One Is Better? 

So, which one is better between PostgreSQL vs. MySQL? The answer to this question depends on the needs of your project and your accessibility to either option. A great starting point to answer this question lies in your web server. If you’re using a specific web- or cloud-hosting service, they might only offer one type of SQL server, or access to one or the other might be a lot more expensive. For instance, a popular cloud-hosting service for Python projects is Python Anywhere. They provide a MySQL server at no additional charge, but upgrading to PostgreSQL is a premium add-on.

If that’s not an issue for the project you’re planning right now, then another consideration would be the server-side language you’re pairing with your SQL server. If you’re programming with PHP, MySQL might be a more attractive option because it has years of proven results with web applications whose primary programming language is PHP.

Next, we recommend looking at what type of application you are designing. If your primary concern is collecting, manipulating, and reporting data for a web application, your best choice is MySQL because that’s what it was designed for. However, if you’re dealing with a more complex use case, like finance, geodata, manufacturing, or scientific data, we recommend using PostgreSQL for its more complex query capabilities.

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