CASE表达式的使用

-- 设置数据库上下文
USE TSQLFundamentals2008;
GO

SELECT productid,productname,categoryid,
    CASE categoryid
        WHEN 1 THEN ‘Beverages‘
        WHEN 2 THEN ‘Condiments‘
        WHEN 3 THEN ‘Dairy Products‘
        WHEN 4 THEN ‘Confections‘
        WHEN 5 THEN ‘Grains/Cereals‘
        WHEN 6 THEN ‘Meat/Poultry‘
        WHEN 7 THEN ‘Produce‘
        WHEN 8 THEN ‘Seafood‘
        ELSE ‘Unkown Category‘
    END AS categoryname
FROM Production.Products;