SQL 怎么合并一列，另一列不重复的值连成字符串

Question

一个表cuslist,有两列customer和manager，想把第一列合并，但是要把第二列不重复的值通过字符串加起来

customer	manager
IBM	张三
IBM	李四
IBM	王五
IBM	王五
Microsoft	赵六
Microsoft	孙七
Microsoft	孙七
Apple	朱八

请问怎么实现可以达到以下这种效果

customer	manager
IBM	张三，李四，王五
Microsoft	赵六，孙七
Apple	朱八

求大佬们帮忙解答一下，不胜感激

Answer 1

SELECT

    customer,
    GROUP_CONCAT(DISTINCT  manager) 
FROM
    cuslist
GROUP BY
customer

Answer 2

SELECT
DISTINCT(customer)
,STUFF((

 SELECT ','+T.manager
 FROM (SELECT customer,manager FROM cuslist GROUP BY customer,manager) AS T
 WHERE T.customer=A.customer
 FOR XML PATH('')),1,1,'')AS manager 

FROM cuslist as A