Mysql 多条件sql语句

我有一个包含英国或美国用户和国家的表格，现在一个用户可以在不同的国家出现多次。我需要选择一个具有唯一用户的列表，其国家或等于英国、美国或两者

这是我尝试的方法，但它似乎不起作用

select user, 
    case 
        when COUNT(*) <= 1 and count(select where = "UK") = count(*) then "UK"
        when COUNT(*) <= 1 and count(select where = "US") = count(*) then "US" 
        when COUNT(*) <= 1 and count(select where = "US") != count(*) then "BOTH"
    END CASE
as country from users; 

---

你可以这样做：

SELECT 
    temp.user,
    if(temp.CountryList = "UK,US", "BOTH", temp.CountryList) as country
FROM
(
     SELECT 
         user,
         group_concat(DISTINCT country ORDER BY country) as CountryList
     FROM USERS
     GROUP BY user
) temp

---

请提供表格结构和一些条目。

SELECT 
    temp.user,
    if(temp.CountryList = "UK,US", "BOTH", temp.CountryList) as country
FROM
(
     SELECT 
         user,
         group_concat(DISTINCT country ORDER BY country) as CountryList
     FROM USERS
     GROUP BY user
) temp