Mysql的空值更改为0

Question

我有这个SQL语句为我的MySQL数据库。

SELECT MAX(customer_ID) AS high_customer_ID FROM `customers`.`customers` WHERE our_customer_ID=1; 

但whene疗法是our_customer_ID = 1没有CUSTOMER_ID那么statment返回null，但我想它返回0怎么做呢。

Answer 1

您可以使用coalesce功能在null的情况下指定一个默认值：

SELECT COALESCE(MAX(customer_ID), 0) AS high_customer_ID 
FROM `customers`.`customers` 
WHERE our_customer_id = 1;