Learn how to access and query a database running inside a Docker container. This article covers:
- Setting up MySQL or PostgreSQL in Docker
- Connecting from the host or using
docker exec - Selecting data from a table using SQL
- Using Docker Compose for simplified setups
Ideal for developers working with Dockerized databases in local development environments.
🐬 Part 1: Accessing a MySQL Container and Running SELECT Queries
✅ Step 1: Start a MySQL Container
bash
docker run --name mysql-container \
-e MYSQL_ROOT_PASSWORD=rootpassword \
-e MYSQL_DATABASE=mydatabase \
-e MYSQL_USER=myuser \
-e MYSQL_PASSWORD=mypassword \
-p 3306:3306 -d mysql:latest
✅ Step 2: Install MySQL Client (If Needed)
Ubuntu:
bash
sudo apt-get update
sudo apt-get install mysql-client
✅ Step 3: Connect from Host
bash
mysql -h 127.0.0.1 -P 3306 -u myuser -p mydatabase
(Then enter the password mypassword)
✅ Step 4: Query the Table
sql
SELECT * FROM mytable;
✅ Optional: Run SQL from Inside the Container
bash
docker exec -it mysql-container mysql -u myuser -pmypassword mydatabase
Then:
sql
SELECT * FROM mytable;
🐘 Part 2: Accessing a PostgreSQL Container and Running SELECT Queries
✅ Step 1: Start a PostgreSQL Container
bash
docker run --name postgres-container \
-e POSTGRES_PASSWORD=mysecretpassword \
-e POSTGRES_DB=mydatabase \
-e POSTGRES_USER=myuser \
-p 5432:5432 -d postgres:latest
✅ Step 2: Install PostgreSQL Client (If Needed)
Ubuntu:
bash
sudo apt-get update
sudo apt-get install postgresql-client
✅ Step 3: Connect from Host
bash
psql -h 127.0.0.1 -p 5432 -U myuser -d mydatabase
(Then enter password mysecretpassword)
✅ Step 4: Query the Table
sql
SELECT * FROM mytable;
✅ Optional: Run SQL from Inside the Container
bash
docker exec -it postgres-container psql -U myuser -d mydatabase
Then:
sql
SELECT * FROM mytable;
📦 Optional: Docker Compose Setup for MySQL/PostgreSQL + Adminer
yaml
version: '3.1'
services:
db:
image: mysql:latest # Or postgres:latest
container_name: db-container
environment:
MYSQL_ROOT_PASSWORD: rootpassword
MYSQL_DATABASE: mydatabase
MYSQL_USER: myuser
MYSQL_PASSWORD: mypassword
# For PostgreSQL use:
# POSTGRES_DB: mydatabase
# POSTGRES_USER: myuser
# POSTGRES_PASSWORD: mysecretpassword
ports:
- "3306:3306" # or "5432:5432"
adminer:
image: adminer
restart: always
ports:
- 8080:8080
Start with:
bash
docker-compose up -d
Access Adminer at http://localhost:8080
📌 Summary Table
TaskMySQL CommandPostgreSQL CommandStart Containerdocker run ... mysqldocker run ... postgresConnect from Hostmysql -h 127.0.0.1 -P 3306 -u myuser -p mydbpsql -h 127.0.0.1 -p 5432 -U myuser -d mydbConnect from Containerdocker exec -it mysql-container mysql ...docker exec -it postgres-container psql ...Run SQLSELECT * FROM mytable;SELECT * FROM mytable;Web Admin Tool (optional)Adminer at http://localhost:8080Adminer at http://localhost:8080