SELECT prod_name
FROM Products;
SElECT prod_id,prod_name,prod_price
FROM Products;
SELECT *
FROM Products;
SELECT DISTINCT vend_id--取不同
FROM Products;
select * from (select rownum rn,Products.prod_name from Products) where rn <=5;
SELECT prod_name
FROM Products
WHERE ROWNUM <=5;--前5列
select prod_name from Products where rownum <= 9 minus select prod_name from Products where rownum <= 4;--5-9列
select* from Products where rownum <= 9 minus select * from Products where rownum <= 4;--5-9列
--字典序
SELECT prod_name
FROM Products
ORDER BY prod_name;
SELECT prod_name,prod_id,prod_price
FROM Products
ORDER by prod_price,prod_name;
--第一行决定出场顺序,第二行是第一,二关键字,可以用第一行的相对位置表示。
SELECT prod_name,prod_id,prod_price--决定出场顺序
FROM Products
ORDER by 3,2;
--指定降序排序
SELECT prod_id,prod_price,prod_name
FROM Products
ORDER by prod_price DESC,prod_id DESC;