使用SUBSTRING_INDEX()需要3个参数：

1. 列名称
2. Delimiter
3. 出现次数

您可以在此找到更多说明文章

查询

SELECT
  SUBSTRING_INDEX(customer_name,' ', 1) as first_name, 
  SUBSTRING_INDEX(customer_name,' ', -1) as last_name FROM customer;

请测试一下：我使用locate函数来定义“ ”的位置。

SELECT 
LEFT(customer_name, LOCATE(' ',customer_name)-1) as first_name,
RIGHT(customer_name, LENGTH(customer_name)-LOCATE(' ',customer_name)) as last_name
FROM customer;

结果集：