How to fix ERROR 1068: Multiple primary key defined in MySQL

SHOW CREATE TABLE your_table_name;

DESCRIBE your_table_name;

CREATE TABLE orders (
    customer_id INT NOT NULL,
    order_date DATE NOT NULL,
    order_id INT NOT NULL,
    PRIMARY KEY (customer_id, order_date)  -- One composite key, two columns
);

CREATE TABLE orders (
    id INT PRIMARY KEY,          -- First primary key
    code INT PRIMARY KEY         -- Second primary key - NOT ALLOWED!
);

CREATE TABLE users (
    user_id INT PRIMARY KEY,
    email VARCHAR(255) PRIMARY KEY,  -- Remove this!
    name VARCHAR(100)
);

CREATE TABLE users (
    user_id INT PRIMARY KEY,
    email VARCHAR(255),  -- Make it UNIQUE if needed
    name VARCHAR(100)
);

CREATE TABLE users (
    user_id INT PRIMARY KEY,
    email VARCHAR(255) UNIQUE,  -- Use UNIQUE constraint instead
    name VARCHAR(100)
);

-- First, drop the existing primary key
ALTER TABLE your_table DROP PRIMARY KEY;

-- Then add the new primary key
ALTER TABLE your_table ADD PRIMARY KEY (column_name);

ALTER TABLE your_table DROP PRIMARY KEY;
ALTER TABLE your_table ADD PRIMARY KEY (column1, column2);

-- Check the current setting
SHOW VARIABLES LIKE 'sql_generate_invisible_primary_key';

-- Disable it for your session
SET sql_generate_invisible_primary_key = OFF;

-- Now your CREATE TABLE or ALTER TABLE will work
CREATE TABLE users (...) ENGINE=InnoDB;

[mysqld]
sql_generate_invisible_primary_key = OFF

-- If creating a new table:
CREATE TABLE users (
    id INT AUTO_INCREMENT PRIMARY KEY,
    email VARCHAR(255) UNIQUE NOT NULL,
    name VARCHAR(100)
);

-- Verify it was created successfully:
SHOW CREATE TABLE users;