Direct answer: both database systems fit most sites, and the right pick depends on what the application needs, not on an abstract claim about which one is faster.
What is the difference between SQL and MySQL
SQL is a query language for relational databases, a standard that describes how to ask for and change data. MySQL is a specific database management system, one of many that implement this language and add its own extensions on top.
The confusion comes from the similar names: SQL is not tied to one vendor, while MySQL is a concrete product with its own SQL dialect, its own set of functions, and behavior details that do not always match other database systems.
What MySQL and PostgreSQL each have: a feature comparison
Below is a table of what each system has, with no "better" or "worse" judgment. These are different architectural choices, and each has its own logic.
| Feature | MySQL / MariaDB | PostgreSQL |
|---|---|---|
| Extension model | pluggable storage engines (InnoDB, MyISAM) | a single storage model, extended through the extensions mechanism |
| Data types | a basic set, strict mode configured separately | a wide set of built-in types, including arrays and composite types |
| JSON handling | a JSON type and functions to work with it | json and jsonb types with indexing of their content |
| Full-text search | a built-in full-text index | built-in full-text search based on tsvector |
| Replication | classic master-slave and group replication | streaming replication and logical replication |
| Transactional DDL | not every schema operation is transactional | schema changes can be rolled back inside a transaction |
| License | GPL, with commercial editions from the brand owner | a permissive license with no restrictions on forks |
| Typical stack | ready-made CMS platforms, control panels, shared hosting | analytics, geospatial data, custom backends |
When MySQL or MariaDB is the easier choice
If the application is a typical CMS, a ready-made control panel, or a project with plenty of existing guides online, MySQL or MariaDB is the more predictable choice: configuration, backups, and common problems are already documented many times over.
The same holds when a site is deployed through a ready hosting panel — most such panels work with MySQL or MariaDB by default. For setting up such a database on a rented server, see the article on MariaDB on a VPS.
When teams choose PostgreSQL
PostgreSQL gets chosen when the application needs complex queries and analytics, strict data type checking at the database level, and the ability to add extensions for a specific task, from geospatial data to vector search.
This is the choice for a custom backend built around specific logic, not for a ready-made CMS. Setting up such a database on your own server is covered in the article on PostgreSQL on a VPS.
What matters equally in both databases
Regardless of the choice, a few things need attention in any database system, and they are often skipped at the start.
- Backups on a schedule, not "whenever someone remembers"
- An explicitly chosen character set and collation, picked once and deliberately
- A connection limit that matches what the server can actually handle
- A separate database user for each application, without shared root access
Can you move from one database system to the other
Moving is possible, but not automatic: syntax and behavior differ in the details, and loading a dump "as is" almost always needs edits.
- Data types do not map one to one, and some need to be redefined by hand
- Auto-increment is implemented through different mechanisms and needs separate setup
- Table and column name case is handled differently
- Built-in date and string functions are named and behave differently
Migrate through a test copy and check every application query, rather than assume the dump will load without edits.
A short conclusion: how to choose if you would rather not
If the site runs on a ready-made CMS or a hosting panel, pick MySQL or MariaDB. If you are writing a custom backend with non-trivial queries, pick PostgreSQL. Everything else gets settled during the work itself, not at the engine-selection stage.