mysql - 将国家组合在一起并计数

Question

我有一张这样的桌子：

-------------------------------
EMP ID|Country    |Emp Level  |
------|-----------|-----------|
102   |UK         |Staff      |
103   |US         |Admin Staff|
104   |CA         |Staff      |
105   |NL         |Admin Staff|
106   |MN         |Intern     |
107   |IN         |Staff      |
108   |UK         |Staff      |
109   |US         |Admin Staff|
110   |IN         |Admin Staff|
------------------------------

在给定以下条件的情况下，我需要计算每个国家/地区每个类别的员工人数：如果国家/地区不在，('UK' or 'US' or 'CA')则将其视为“全球”。所以我们的答案应该是：

------------------------------
|Country    |Emp Level  |Count|
|-----------|-----------|-----
|UK         |Staff      |2
|US         |Admin Staff|2
|CA         |Staff      |1
|Global     |Admin Staff|2
|Global     |Intern     |1
|Global     |Staff      |1

到目前为止，我可以计算每个国家/地区的每个类别的员工人数，但无法将不在给定集合中的国家/地区归为一类，并将它们计算并显示为全球。

Answer 1

SELECT   Country, EmpLevel, COUNT(*) AS Count
FROM     my_table
WHERE    Country IN ('UK', 'US', 'CA')
GROUP BY Country, EmpLevel

UNION

SELECT   'Global', EmpLevel, COUNT(*) AS Count
FROM     my_table
WHERE    Country NOT IN ('UK', 'US', 'CA')
GROUP BY EmpLevel

在sqlfiddle上查看。

Answer 2

SELECT  
    CASE WHEN Country IN ('UK', 'US', 'CA') THEN Country ELSE 'Global' END
      AS Country,
    EmpLevel, 
    COUNT(*) AS Count
FROM
    tableX
GROUP BY 
    CASE WHEN Country IN ('UK', 'US', 'CA') THEN Country ELSE 'Global' END, 
    EmpLevel ;

---

此查询与@eggyal 和@duffymo 的查询之间的结果将有所不同 - 如果有NULLin column行Country。此查询将计算'Global'组中的那些行，其他查询根本不计算它们。

Answer 3

你试过这个吗？

select country as cou, emp_level as emp, count(*)
from your_table
where country in ('UK', 'US', 'CA')
group by cou, emp
order by cou, emp
union
select 'global', emp_level as emp, count(*)
from your_table
where country not in ('UK', 'US', 'CA')
group by emp
order by emp

Answer 4

也许这样的事情会起作用（未经测试，可能需要更多的工作）

SELECT CASE WHEN Country NOT IN ('US','UK','CA') THEN 'Global' ELSE Country, Emp_Level, COUNT(*)
FROM table_name
GROUP BY Country, Emp_Level