sql - 为什么 Oracle 数据库不适用于 as

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

但是下面这段代码有效

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，之前我习惯用 MySQL 编写代码。 oracle中如何使用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