mysql update和insert

UPDATE table_name SET column1=value1 WHERE condition;

INSERT INTO table_name (column1, column2, ...) 
SELECT value1, value2, ... 
WHERE NOT EXISTS (SELECT 1 FROM table_name WHERE primary_key_column=value);

INSERT INTO table_name (primary_key_column, column1, column2, ...) 
VALUES (value, value1, value2, ...) 
ON DUPLICATE KEY UPDATE column1=VALUES(column1), column2=VALUES(column2);

-- 更新操作示例
UPDATE users SET age=31 WHERE id=1;

-- 插入操作示例
INSERT INTO users (id, name, age) VALUES (2, 'Alice', 28);

-- 批量插入示例
INSERT INTO users (id, name, age) VALUES 
(3, 'Bob', 29),
(4, 'Charlie', 30);

-- 使用事务批量更新示例
START TRANSACTION;
UPDATE products SET stock=stock-10 WHERE id IN (1,2,3);
UPDATE orders SET status='shipped' WHERE id IN (10,11,12);
COMMIT;