为什么Oracle数据库不能用于

Question

此代码在Oracle

中不起作用

SELECT cost
FROM
    (
            SELECT shoppingserviceid,cost,bsid
            FROM service JOIN shopping_service 
            ON service.serviceid = shopping_service.serviceid 
    ) as S
WHERE cost = 2000

但是下面的代码可以使用

SELECT cost
FROM
        (
            SELECT shoppingserviceid,cost,bsid
            FROM service JOIN shopping_service 
            ON service.serviceid = shopping_service.serviceid 
        ) 
WHERE cost = 2000

好吧，我是oracle的新手，在我习惯MySQL编码之前。如何在oracle中使用AS语句？

Answer 1

Oracle中的表别名不使用AS关键字：

SELECT cost -- can also use S.cost
FROM
        (
            SELECT shoppingserviceid,cost,bsid
            FROM service JOIN shopping_service 
            ON service.serviceid = shopping_service.serviceid 
        ) S
WHERE cost = 2000 -- Can also use S.cost