mysql - 是否可以在 MySQL 中创建一个表达式作为默认值的列？

Question

如何在 MySQL 中实现这一点:

CREATE TABLE employee (
  employeemonthly DECIMAL(10,2), 
  employeeyearly DECIMAL(10,2) DEFAULT employeemonthly*12
);

Answer 1

为此使用插入触发器。像这样

DELIMITER |

CREATE TRIGGER default_yearly BEFORE INSERT ON employee
  FOR EACH ROW BEGIN   
    SET NEW.employeeyearly = NEW.employeemonthly * 12;
  END;
|

DELIMITER ;