How to fix ERROR 1115: Unknown character set in MySQL

First, verify which MySQL version you're running. Log in to MySQL and check:

SELECT VERSION();

If you're running MySQL 5.5.2 or earlier and the error mentions utf8mb4, you need to upgrade to at least 5.5.3. For other unsupported charsets, check the MySQL documentation to determine the minimum version that supports it.

Run this command to see all character sets supported by your MySQL server:

SHOW CHARACTER SET;

This displays the complete list of available charsets. Compare the charset from your error message with this list. If it's not present, the charset is not supported on your server version.

Review your SQL statements and configuration for common typos:

- Correct: utf8mb4 (no hyphens)
- Incorrect: utf-8mb4 or utf_8mb4
- Correct: utf8
- Incorrect: UTF-8 or utf-8

Character set names in MySQL are case-insensitive but must not contain hyphens. If you find typos, correct them in your SQL file, application config, or connection string.

If you're importing a dump file from a newer MySQL version, replace the unsupported charset before importing:

Using sed (Linux/macOS):

sed -i 's/CHARACTER SET utf8mb4/CHARACTER SET utf8/g' dump.sql
sed -i 's/utf8mb4/utf8/g' dump.sql

Using find and replace (Windows):
Open the dump file in a text editor and use find/replace to change all instances of the charset.

Then import the modified file:

mysql -u root -p database_name < dump.sql

If the charset should be supported on your version but isn't, upgrade MySQL to a newer version:

Ubuntu/Debian:

sudo apt-get update
sudo apt-get upgrade mysql-server

macOS (with Homebrew):

brew upgrade mysql

Docker:
Update your MySQL Docker image tag to a newer version in docker-compose.yml or your Dockerfile.

After upgrading, restart MySQL and re-run your import or SQL statements.

If you're connecting from an application, ensure the connection specifies a supported charset:

MySQL client:

mysql -u root -p --default-character-set=utf8 database_name

Python:

import mysql.connector
conn = mysql.connector.connect(
  host="localhost",
  user="root",
  password="password",
  database="mydb",
  charset="utf8"
)

PHP (MySQLi):

$conn = new mysqli("localhost", "root", "password", "mydb");
$conn->set_charset("utf8mb4");

Node.js:

const connection = mysql.createConnection({
  host: 'localhost',
  user: 'root',
  password: 'password',
  database: 'mydb',
  charset: 'utf8mb4'
});