mysql insert重复数据

CREATE TABLE users (
    id INT PRIMARY KEY,
    username VARCHAR(50) UNIQUE
);

INSERT INTO users (id, username) VALUES (1, 'john_doe');
INSERT INTO users (id, username) VALUES (1, 'jane_doe'); -- 这将导致主键冲突

CREATE TABLE products (
    sku VARCHAR(50) PRIMARY KEY,
    name VARCHAR(100)
);

INSERT INTO products (sku, name) VALUES ('SKU001', 'Product A');
INSERT INTO products (sku, name) VALUES ('SKU001', 'Product B'); -- 这将导致唯一约束冲突

INSERT IGNORE INTO users (id, username) VALUES (1, 'jane_doe');

INSERT INTO users (id, username) VALUES (1, 'jane_doe')
ON DUPLICATE KEY UPDATE username = 'jane_dole';

REPLACE INTO users (id, username) VALUES (1, 'jane_doe');