How to fix ERROR 1045 (28000): Access denied for user in MySQL

# Basic connection attempt
mysql -u username -p
# Enter password when prompted

# Connection with explicit hostname
mysql -u username -p -h localhost

# Connection with hostname and database
mysql -u username -p -h 127.0.0.1 database_name

# All parameters on command line (less secure)
mysql -u username -pYourPassword -h localhost database_name

# Try connecting without providing password
mysql -u root

# Or explicitly with no password
mysql -u root -p
# Just press Enter when prompted for password

# If you know root password
mysql -u root -p

# If root has no password
mysql -u root

# Or with localhost specified
mysql -u root -p -h localhost

-- List all users in the mysql.user table
SELECT user, host FROM mysql.user;

-- Check specific user
SELECT user, host, authentication_string FROM mysql.user WHERE user = 'myuser';

-- See detailed information about a user
SELECT * FROM mysql.user WHERE user = 'myuser' \G

-- Check if user exists for specific host
SELECT user, host FROM mysql.user WHERE user = 'myuser' AND host = 'localhost';

-- Create user for localhost only
CREATE USER 'newuser'@'localhost' IDENTIFIED BY 'password123';

-- Create user for any host (remote access)
CREATE USER 'newuser'@'%' IDENTIFIED BY 'password123';

-- Create user for specific IP address
CREATE USER 'newuser'@'192.168.1.100' IDENTIFIED BY 'password123';

-- Create multiple host entries for same user
CREATE USER 'myapp'@'localhost' IDENTIFIED BY 'password';
CREATE USER 'myapp'@'192.168.1.5' IDENTIFIED BY 'password';

-- MySQL 8.0+
ALTER USER 'username'@'localhost' IDENTIFIED BY 'newpassword';

-- MySQL 5.7 and earlier
SET PASSWORD FOR 'username'@'localhost' = PASSWORD('newpassword');

-- Then apply changes
FLUSH PRIVILEGES;

-- See what privileges a user has
SHOW GRANTS FOR 'myuser'@'localhost';

-- Check all permissions in detail
SELECT * FROM mysql.user WHERE user = 'myuser' \G
SELECT * FROM mysql.db WHERE user = 'myuser' \G

-- Grant all privileges on specific database
GRANT ALL PRIVILEGES ON mydatabase.* TO 'myuser'@'localhost';

-- Grant specific privileges (read-only)
GRANT SELECT ON mydatabase.* TO 'myuser'@'localhost';

-- Grant multiple specific privileges
GRANT SELECT, INSERT, UPDATE, DELETE ON mydatabase.* TO 'myuser'@'localhost';

-- Grant privileges on all databases
GRANT ALL PRIVILEGES ON *.* TO 'myuser'@'localhost';

-- Grant with GRANT option (allows user to grant to others)
GRANT ALL PRIVILEGES ON mydatabase.* TO 'myuser'@'localhost' WITH GRANT OPTION;

-- Apply changes immediately
FLUSH PRIVILEGES;

# Disconnect from root and try new user
mysql -u myuser -p -h localhost mydatabase

-- See all users and their allowed hosts
SELECT user, host FROM mysql.user ORDER BY user;

-- Check specific user's hosts
SELECT user, host FROM mysql.user WHERE user = 'myapp';

-- 127.0.0.1 is not the same as localhost in MySQL
-- Create another entry for the IP address
CREATE USER 'myuser'@'127.0.0.1' IDENTIFIED BY 'password';
GRANT ALL PRIVILEGES ON mydatabase.* TO 'myuser'@'127.0.0.1';

-- Or use localhost (which typically resolves to 127.0.0.1)
mysql -u myuser -p -h localhost mydatabase

-- Create user for remote host's IP
CREATE USER 'myuser'@'192.168.1.50' IDENTIFIED BY 'password';
GRANT ALL PRIVILEGES ON mydatabase.* TO 'myuser'@'192.168.1.50';

-- Or allow connection from any host (less secure)
CREATE USER 'myuser'@'%' IDENTIFIED BY 'password';
GRANT ALL PRIVILEGES ON mydatabase.* TO 'myuser'@'%';

-- See current connection info
SELECT USER();

-- See which hosts current user can use
SELECT CURRENT_USER();

FLUSH PRIVILEGES;

# Linux/Mac
sudo systemctl stop mysql

# Or
sudo /usr/local/mysql/support-files/mysql.server stop

# macOS with Homebrew
brew services stop mysql

# Windows (if running as service)
net stop MySQL80

# Linux/Mac - start without password authentication
sudo mysqld_safe --skip-grant-tables &

# Windows
mysqld --skip-grant-tables

# Connect to MySQL without authentication
mysql -u root

-- Flush privileges first (may be needed on some versions)
FLUSH PRIVILEGES;

-- MySQL 8.0+
ALTER USER 'root'@'localhost' IDENTIFIED BY 'new_password';

-- MySQL 5.7 and earlier
SET PASSWORD FOR 'root'@'localhost' = PASSWORD('new_password');

-- Exit
EXIT;

# Linux/Mac
sudo systemctl restart mysql

# macOS with Homebrew
brew services restart mysql

# Windows
net start MySQL80

mysql -u root -p
# Enter new_password when prompted

# Linux - check service status
sudo systemctl status mysql

# macOS - check if running
brew services list | grep mysql

# Windows - check Services
sc query MySQL80

# Or use netstat/ss to check if port is listening
sudo netstat -tulpn | grep 3306
sudo ss -tulpn | grep 3306

# Linux
sudo systemctl start mysql

# macOS with Homebrew
brew services start mysql

# Windows
net start MySQL80

# Or direct command (various systems)
mysqld_safe &

# Test connection to localhost
mysql -h 127.0.0.1 -u root -p

# Test from command line with nc (netcat)
nc -zv localhost 3306

# Check MySQL configuration for port number
grep port /etc/mysql/mysql.conf.d/mysqld.cnf

# Or
grep port /etc/my.cnf

# Get MySQL version
mysql --version
mysqld --version

# Check if MySQL is actually running (process list)
ps aux | grep mysqld

# Or on Windows
tasklist | findstr mysqld

# Typical log locations
tail -f /var/log/mysql/error.log
tail -f /var/log/mysql/mysql.log

# Or check last lines
grep -i error /var/log/mysql/error.log | tail -20