如何獲取Oracle中特定記錄的計數？

Question

我從員工表中獲取各種狀態，該員工表有230個記錄，狀態低於5。 我已經編寫了查詢以獲取每個狀態的計數但現在需要將狀態A和B的組合計數作為AB。

我的查詢：

SELECT DISTINCT Status AS Status,
           COUNT(Status ) AS StatusCount
    FROM EMPLOYEE
    GROUP BY Status

我的查詢輸出是：

Status    Count
A           100
B           50
C           30
D           10
E           40

我希望結果作為A＆B組合並保持相同。

Status      Count
A&B          150
C             30
D             10
E             40

Answer 1

使用case

SELECT case when Status in ('A','B') 
            then 'A&B'
            else Status
       end AS Status,
       COUNT(Status) AS StatusCount
FROM EMPLOYEE
GROUP BY case when Status in ('A','B') 
              then 'A&B'
              else Status
         end

Answer 2

使用也可以使用decode

SELECT decode(status,'A','A&B','B','A&B',status) AS Status,
       COUNT(status) AS StatusCount
FROM EMPLOYEE
GROUP BY decode(status,'A','A&B','B','A&B',status) AS Status