MySQL vs PostgreSQL: Which Database Should You Use?

If you are starting a new application, sooner or later someone asks: MySQL or PostgreSQL? Both are free, open-source relational databases with decades of production use behind them. Both run some of the largest websites in the world. The MySQL vs PostgreSQL decision is therefore less about which one is "better" and more about which fits your team, your data and your hosting. This article lays out the real differences without the tribal loyalty.

A quick introduction to each

MySQL was first released in the mid-1990s and became the "M" in the LAMP stack (Linux, Apache, MySQL, PHP). It is owned by Oracle, which offers a free Community Edition and paid editions. MariaDB is a community fork created by MySQL's original developers; it is largely compatible but has diverged over time, so treat it as a related but separate product.

PostgreSQL (often "Postgres") grew out of a research project at the University of California, Berkeley. It is developed by a global community under a permissive licence, with no single company owning it. It has a reputation for strict standards compliance and extensibility.

MySQL vs PostgreSQL side by side

Where PostgreSQL tends to shine

Complex queries and analytics

PostgreSQL's query planner handles complex joins, subqueries and window functions well, and it has offered features such as common table expressions (WITH queries) for a long time. MySQL added CTEs and window functions in version 8.0, which closed much of the gap, but many teams still find Postgres more comfortable for reporting-heavy work.

Data integrity

Postgres is strict by default. It rejects invalid dates and values that do not fit a column rather than silently adjusting them. Modern MySQL enables strict SQL mode by default too, but older installations and some hosting setups still run with looser settings, which can let bad data in quietly.

Specialised data

Its extension system is a genuine advantage. PostGIS turns Postgres into a full geographic database. pgvector adds vector similarity search, used for AI features such as semantic search. Array types, range types and JSONB let you model unusual data without bolting on another system.

Safer schema changes

Because Postgres supports transactional DDL (data definition language: CREATE, ALTER, DROP), a migration that fails halfway can roll back cleanly:

BEGIN;
ALTER TABLE orders ADD COLUMN currency char(3) NOT NULL DEFAULT 'INR';
CREATE INDEX idx_orders_currency ON orders (currency);
-- something goes wrong?
ROLLBACK;  -- both changes are undone

In MySQL, each ALTER TABLE commits immediately, so a failed multi-step migration can leave the schema half-changed.

Where MySQL tends to shine

Simple, read-heavy web workloads

For typical web applications doing many small primary-key lookups, MySQL with InnoDB is fast, well understood and easy to operate. Its clustered primary key design (rows are physically stored in primary key order) suits this pattern.

Ecosystem and hosting

WordPress, Magento, many PHP frameworks and countless off-the-shelf applications target MySQL first. Nearly every hosting provider offers it, and tooling such as phpMyAdmin is familiar to a huge pool of developers.

Operational familiarity

Replication in MySQL has been used at very large scale for many years, and there is a deep pool of operators who know its quirks. Postgres requires a little more understanding of concepts such as vacuum (its background clean-up of old row versions) to run well under heavy write loads.

Performance: it depends on the workload

You will find benchmarks showing either database winning. Results depend heavily on the workload, configuration, hardware and version, so treat generic benchmarks with caution. In practice, schema design, indexing and query quality affect performance far more than the choice between these two engines. If performance is the deciding factor, test your own representative queries on both.

How to choose

Choose PostgreSQL if:

• You are building a new custom application and have no constraint pulling you elsewhere.
• You expect complex reporting, geographic data, JSON-heavy records or vector search.
• You value strict data validation and safe schema migrations.

Choose MySQL if:

• You are running software built for it, such as WordPress or Magento.
• Your team and hosting are already built around MySQL.
• Your workload is mostly straightforward reads and writes by primary key.

Either will serve a typical business application well. Switching later is possible but costs real effort, so it is worth deciding deliberately. We work with both in our database management and web application development projects, and the right answer genuinely varies. The official PostgreSQL documentation and MySQL documentation are the best references for version-specific features.

Key takeaways

• Both are mature, free and capable; the MySQL vs PostgreSQL choice is about fit, not quality.
• PostgreSQL leads on extensibility, advanced indexing, strictness and transactional schema changes.
• MySQL leads on ubiquity, hosting support and compatibility with popular off-the-shelf software.
• Good schema and query design matter more to speed than the engine you pick.