练习题
1. 编写一条SQL语句,从 product(商品) 表中选取出“登记日期(regist_date)在2009年4月28日之后”的商品,查询结果要包含 product name 和 regist_date 两列。
SELECT
product_name,
regist_date
FROM
product
WHERE
regist_date < '2009-04-28';
2. 请说出对product 表执行如下3条SELECT语句时的返回结果。
1.
SELECT *
FROM product
WHERE purchase_price = NULL;
返回结果为空
2.
SELECT *
FROM product
WHERE purchase_price <> NULL;
返回结果为空
3.
SELECT *
FROM product
WHERE product_name > NULL;
返回结果为空
3.
SELECT
product_name,
sale_price,
purchase_price
FROM
product
WHERE
( sale_price - purchase_price ) >= 500;
4.
SELECT
product_name,
product_type,
( sale_price * 0.9 - purchase_price ) AS profit
FROM
product
WHERE
product_type IN ( '办公用品', '厨房用具' )
AND ( sale_price * 0.9 - purchase_price ) > 100;
5. 请指出下述SELECT语句中所有的语法错误。
SELECT product_id, SUM(product_name)
--本SELECT语句中存在错误。
FROM product
GROUP BY product_type
WHERE regist_date > '2009-09-01';
- SUM函数使用的是全角的括号
- SUM函数不能用于字符类型
6.
SELECT
product_type,
SUM( sale_price ),
SUM( purchase_price )
FROM
product
GROUP BY
product_type
HAVING
SUM( sale_price ) > SUM( purchase_price ) * 1.5;
7.
SELECT
*
FROM
product
ORDER BY
-regist_date, purchase_price;
标签:purchase,product,price,wonderful,sql,Task02,WHERE,SUM,SELECT
From: https://www.cnblogs.com/qianmo39/p/17576192.html