Question

我有一个表（在Oracle数据库中），如下所示：

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

我希望输出看起来像下表：

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

这可能吗？

Answer 1

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

Answer 2

您应该在客户端代码中执行此操作，而不是在数据库级别执行此操作。

但是，如果有一个包含映射的附加表，则可能：

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)

如何在select语句中分类

2 个答案: