mysql 更新单个表

-- 更新单个字段
UPDATE users SET age = 30 WHERE id = 1;

-- 基于条件更新多个字段
UPDATE orders SET status = 'completed', amount = 150 WHERE order_id = 101;

-- 批量更新
UPDATE products SET price = price * 1.1 WHERE category = 'electronics';

-- 检查条件
SELECT * FROM users WHERE id = 1;

-- 确保权限
SHOW GRANTS FOR 'username'@'localhost';

-- 提交事务
START TRANSACTION;
UPDATE users SET age = 30 WHERE id = 1;
COMMIT;

-- 使用锁机制
START TRANSACTION;
SELECT * FROM users WHERE id = 1 FOR UPDATE;
UPDATE users SET age = 30 WHERE id = 1;
COMMIT;

-- 调整事务隔离级别
SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
START TRANSACTION;
UPDATE users SET age = 30 WHERE id = 1;
COMMIT;