如何在SELECT語句

Question

我有一個表（在Oracle數據庫）類，就像下面：

department 
---------- 
Finance 
Sales 
Programmer 
Network Admin 
System Support 

我想有看起來像下表中的輸出：

department 
---------- 
Finance 
Sales 
IT (those category other than Finance and Sales will group under 'IT') 

這可能嗎？

Answer 1

SELECT DISTINCT 
CASE 
    WHEN department IN ('Programmer', 'Network Admin', 'System Support') THEN 'IT' 
    ELSE department 
END 
FROM yourTable 

Answer 2

這是您應該在客戶端代碼中執行的操作，而不是在數據庫級別執行的操作。

然而，用含有映射一個額外的表這將是可能的：

INSERT INTO mappings (department, mapping) VALUES ('Programmer', 'IT'); 
INSERT INTO mappings (department, mapping) VALUES ('Admin', 'IT'); 
INSERT INTO mappings (department, mapping) VALUES ('Support', 'IT'); 

SELECT t.*, COALESCE(m.mapping, t.department) FROM table t 
LEFT JOIN mappings m ON (m.department = t.department)