即使該存儲桶中的項目計數爲0，如何使用大小寫聲明保留存儲桶？

Question

下面是我爲這個問題創建了一個名爲「Salary_table」的數據表：

所以我想找到每個部門的每個薪金桶的員工數量。桶是

"<$100" "$100-$200" and ">$200" 

所需的輸出是：

下面是我爲實現這一任務的代碼：

select distinct(st.department) as "Department", 
sb.salary_bucket as "salary range", count(*) 
from Salary_table st 
Left join (
    select department, employee, case 
     when salary < 100 then "<$100" 
     when salary between 100 and 200 then "$100-$200" 
     else ">$200" 
     end 
     as salary_bucket 
    from Salary_table 
) sb 
on sb.employee = st.employee 
group by st.department, sb.salary_bucket 
order by st.department, sb.salary_bucket 
; 

，但我的輸出是有點短的什麼IM期待：

有兩個問題，我的電流輸出：

1. 0員工收入的工資在桶範圍內未列出的桶;我想它被列爲一個值爲「0」
2. 儘管我在聲明「order by」中添加了薪水桶，但它並不是正確的順序，但我認爲它是b/c的文本，所以不能真正去做。

我真的很感激一些提示和指導如何解決/實現上面提到的這兩個問題。非常感謝！

我已經試過

1. 我試圖用「左連接」，但輸出師出同
2. 我嘗試「按訂單」的條款加入，但似乎沒有對文字工作桶

Answer 1

你是在正確的軌道上，但這個想法有點複雜。使用cross join獲取所有行 - 桶和部門。然後使用left join的匹配信息，使最後group by的聚合：

select d.department, b.salary_bucket, 
     count(sb.department) as cnt 
from (select '<$100' as salary_bucket union all 
     select '$100-$200' union all 
     select '>$200' 
    ) b cross join 
    (select distinct department from salary_table 
    ) d left join 
    (select department, employee, 
      (case when salary < 100 then '<$100' 
        when salary between 100 and 200 then '$100-$200' 
        else '>$200' 
       end) as salary_bucket 
     from Salary_table 
    ) sb 
    on sb.department = d.department and 
     sb.salary_bucket = b.salary_bucket 
group by d.department, b.salary_bucket;