是否可以使用表达式作为默认值在 MySQL 中创建列? [英] Is it possible to create a column in MySQL with an expression as a default value?

问题描述

如何在 MySQL 中实现这一点:

How would one implement this in MySQL:

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

推荐答案

为此使用插入触发器.像这样

use a insert trigger for that. Something like this

DELIMITER |

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

DELIMITER ;

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