Table: Sales
+--------------+---------+
| Column Name | Type |
+--------------+---------+
| sale_id | int |
| product_name | varchar |
| sale_date | date |
+--------------+---------+
sale_id is the primary key for this table.
Each row of this table contains
the product name and the date it was sold.
Since table Sales was filled manually in the year 2000, product_name may contain leading and/or trailing white spaces, also they are case-insensitive.
Write an SQL query to report
product_name
in lowercase without leading or trailing white spaces.
sale_date
in the format ('YYYY-MM')
total
the number of times the product was sold in this month.
Return the result table ordered by product_name
in ascending order, in case of a tie order it by sale_date
in ascending order.
The query result format is in the following example.
Sales
+------------+------------------+--------------+
| sale_id | product_name | sale_date |
+------------+------------------+--------------+
| 1 | LCPHONE | 2000-01-16 |
| 2 | LCPhone | 2000-01-17 |
| 3 | LcPhOnE | 2000-02-18 |
| 4 | LCKeyCHAiN | 2000-02-19 |
| 5 | LCKeyChain | 2000-02-28 |
| 6 | Matryoshka | 2000-03-31 |
+------------+------------------+--------------+
Result table:
+--------------+--------------+----------+
| product_name | sale_date | total |
+--------------+--------------+----------+
| lcphone | 2000-01 | 2 |
| lckeychain | 2000-02 | 2 |
| lcphone | 2000-02 | 1 |
| matryoshka | 2000-03 | 1 |
+--------------+--------------+----------+
In January, 2 LcPhones were sold,
please note that the product names are
not case sensitive and may contain spaces.
In Februery, 2 LCKeychains and 1 LCPhone were sold.
In March, 1 matryoshka was sold.
来源:力扣(LeetCode) 链接:https://leetcode-cn.com/problems/fix-product-name-format 著作权归领扣网络所有。商业转载请联系官方授权,非商业转载请注明出处。
upper\ucase
,小写lower\lcase
trim
去除空格,ltrim、rtrim
只去除左侧或者右侧空格# Write your MySQL query statement below
select product_name, sale_date, count(*) total
from
(
select
lcase(trim(product_name)) product_name,
date_format(sale_date,'%Y-%m') sale_date
from Sales
) t
group by product_name, sale_date
order by product_name, sale_date