假设你要更新的表为books,列为price,当前要更新的数据ID(标识列)为1update books set price=(select round((select price from books where id=1)/2,1)) where id=1下面来说明1.select price from books where id=1查出你要更新的初始价格是多少2.用select round(数字,精度)来四舍五入例如select round(63.543,1)结果为63.53.将四舍五入的值更新到表中update books set price=(select round((select pric