PostgreSQL vs MySQL: Which Database for Your Project?

PostgreSQL vs MySQL: The Ultimate Database Comparison

PostgreSQL and MySQL are the two dominant open-source databases. Both are mature, performant, and widely used. But they have different strengths – here's how to determine which is right for your project.

The Basics

PostgreSQL

• Type: Object-relational database
• License: PostgreSQL License (very permissive)
• Initial Release: 1996
• Philosophy: Feature richness and standards compliance

MySQL

• Type: Relational database
• License: GPL (+ commercial license from Oracle)
• Initial Release: 1995
• Philosophy: Simplicity and performance

Feature Comparison

Feature	PostgreSQL	MySQL
ACID Compliance	Full	Full (with InnoDB)
JSON Support	Native (JSONB)	JSON data type
Full-Text Search	Built-in	Built-in
Replication	Streaming + Logical	Master-Slave, Group
Partitioning	Declarative	Range, List, Hash
Stored Procedures	PL/pgSQL, Python, Perl	SQL/PSM
Materialized Views	Yes	No
Foreign Data Wrappers	Yes	No
Window Functions	Comprehensive	Since 8.0
CTEs (WITH)	Recursive	Since 8.0

When to Choose PostgreSQL?

1. Complex Queries

PostgreSQL excels at complex analytical queries:

sqlCopy
-- Hierarchical query with recursive CTE
WITH RECURSIVE org_tree AS (
  SELECT id, name, manager_id, 1 AS level
  FROM employees
  WHERE manager_id IS NULL

  UNION ALL

  SELECT e.id, e.name, e.manager_id, ot.level + 1
  FROM employees e
  JOIN org_tree ot ON e.manager_id = ot.id
)
SELECT * FROM org_tree ORDER BY level, name;

-- Window Functions for ranking
SELECT
  product_name,
  category,
  price,
  RANK() OVER (PARTITION BY category ORDER BY price DESC) as price_rank,
  AVG(price) OVER (PARTITION BY category) as avg_category_price
FROM products;

2. JSON Data

PostgreSQL's JSONB is optimized for semi-structured data:

sqlCopy
-- JSONB column with index
CREATE TABLE orders (
  id SERIAL PRIMARY KEY,
  customer_id INT,
  items JSONB,
  created_at TIMESTAMPTZ DEFAULT NOW()
);

-- GIN index for fast JSON search
CREATE INDEX idx_orders_items ON orders USING GIN (items);

-- Query JSON data
SELECT * FROM orders
WHERE items @> '[{"product_id": 123}]';

-- Aggregate JSON
SELECT
  customer_id,
  jsonb_agg(items) as all_items
FROM orders
GROUP BY customer_id;

3. Geospatial (PostGIS)

With PostGIS, PostgreSQL leads for geodata:

sqlCopy
-- Enable PostGIS
CREATE EXTENSION postgis;

-- Locations with geometry
CREATE TABLE locations (
  id SERIAL PRIMARY KEY,
  name VARCHAR(100),
  geom GEOMETRY(Point, 4326)
);

-- All locations within 5km radius
SELECT name, ST_Distance(geom, 'POINT(-0.1276 51.5074)'::geography) as distance
FROM locations
WHERE ST_DWithin(geom, 'POINT(-0.1276 51.5074)'::geography, 5000)
ORDER BY distance;

4. Data Integrity

PostgreSQL offers comprehensive constraints:

sqlCopy
-- Partial Unique Constraints
CREATE UNIQUE INDEX idx_active_subscription
ON subscriptions (user_id)
WHERE status = 'active';

-- Check Constraints
ALTER TABLE products
ADD CONSTRAINT price_positive CHECK (price > 0);

-- Exclusion Constraints (no overlap)
CREATE TABLE reservations (
  room_id INT,
  during TSTZRANGE,
  EXCLUDE USING GIST (room_id WITH =, during WITH &&)
);

When to Choose MySQL?

1. Simple CRUD Operations

MySQL is optimized for fast read/write operations:

sqlCopy
-- Simple queries are very fast
SELECT * FROM users WHERE id = 12345;
SELECT * FROM products WHERE category_id = 5 LIMIT 20;

-- Bulk Inserts
INSERT INTO logs (message, level, created_at)
VALUES
  ('Request processed', 'INFO', NOW()),
  ('Cache hit', 'DEBUG', NOW()),
  ('Response sent', 'INFO', NOW());

2. Web Applications (LAMP Stack)

MySQL integrates perfectly with:

• WordPress
• Drupal
• Magento
• Laravel
• Ruby on Rails

phpCopy
// PHP with MySQL
$pdo = new PDO('mysql:host=localhost;dbname=app', 'user', 'pass');
$stmt = $pdo->prepare('SELECT * FROM posts WHERE author_id = ?');
$stmt->execute([$authorId]);
$posts = $stmt->fetchAll(PDO::FETCH_ASSOC);

3. Read-Heavy Workloads

MySQL's read replication is easy to set up:

sqlCopy
-- On the Master
SHOW MASTER STATUS;

-- On the Replica
CHANGE REPLICATION SOURCE TO
  SOURCE_HOST='master.example.com',
  SOURCE_USER='repl_user',
  SOURCE_PASSWORD='password',
  SOURCE_LOG_FILE='mysql-bin.000001',
  SOURCE_LOG_POS=12345;

START REPLICA;

4. Managed Services

Nearly all cloud providers offer MySQL:

• AWS RDS, Aurora MySQL
• Google Cloud SQL
• Azure Database for MySQL
• PlanetScale (Vitess-based)

Performance Comparison

Benchmarks (typical results)

Scenario	PostgreSQL	MySQL
Simple SELECT by PK	95k QPS	110k QPS
Complex JOINs	Faster	Slower
Bulk INSERT	50k/s	70k/s
JSON Operations	Faster	Slower
Concurrent Writes	Better	MVCC overhead

Important: Benchmarks vary greatly depending on configuration, hardware, and use case. Test with your real data!

Migration Between Systems

From MySQL to PostgreSQL

bashCopy
# With pgloader
pgloader mysql://user:pass@localhost/dbname \
         postgresql://user:pass@localhost/newdb

# Or manually:
# 1. Export schema
mysqldump --no-data dbname > schema.sql

# 2. Convert schema (adjust data types)
# INT AUTO_INCREMENT → SERIAL
# DATETIME → TIMESTAMP
# TINYINT(1) → BOOLEAN
# TEXT/MEDIUMTEXT/LONGTEXT → TEXT

# 3. Export/import data
mysqldump --no-create-info --complete-insert dbname > data.sql
psql newdb < data.sql

Important Differences When Migrating

MySQL	PostgreSQL
``` backticks	"double quotes"
AUTO_INCREMENT	SERIAL / IDENTITY
LIMIT 10, 20	LIMIT 20 OFFSET 10
NOW()	NOW() / CURRENT_TIMESTAMP
IFNULL()	COALESCE()
GROUP_CONCAT()	STRING_AGG()
ENUM('a','b')	CREATE TYPE ... AS ENUM

ORM Support

Both databases are supported by all major ORMs:

Node.js (Prisma)

javascriptCopy
// prisma/schema.prisma
datasource db {
  provider = "postgresql"  // or "mysql"
  url      = env("DATABASE_URL")
}

model User {
  id    Int     @id @default(autoincrement())
  email String  @unique
  posts Post[]
}

// Same code for both databases
const users = await prisma.user.findMany({
  include: { posts: true }
});

Python (SQLAlchemy)

pythonCopy
from sqlalchemy import create_engine

# PostgreSQL
engine = create_engine('postgresql://user:pass@localhost/db')

# MySQL
engine = create_engine('mysql+pymysql://user:pass@localhost/db')

# Rest of the code remains identical

Hosting Options

PostgreSQL

Provider	Specialty
Supabase	Firebase alternative with Postgres
Neon	Serverless, Branching
Railway	Simple deployment
AWS RDS	Enterprise-ready
Render	Free tier

MySQL

Provider	Specialty
PlanetScale	Serverless, Git-like Branching
AWS Aurora	MySQL-compatible, highly available
DigitalOcean	Simple Managed DB
Vitess	Horizontal Scaling

Conclusion and Recommendation

PostgreSQL when:

• Complex data models and queries
• JSON data is important
• Geodata is needed
• Data integrity is highest priority
• You want to use advanced SQL features

MySQL when:

• Simple CRUD applications
• Existing MySQL expertise in team
• WordPress/Drupal/Magento
• Maximum read performance required
• Broad cloud support important

Our Practice at Balane Tech

We primarily use PostgreSQL for:

• New projects
• Complex business logic
• Applications with JSON data

We use MySQL for:

• Existing WordPress projects
• Client requirement for MySQL
• Simple web applications

Both databases are excellent. The "right" choice depends on your specific requirements.