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题解 | #将两个 SELECT 语句结合起来（一）#

select prod_id,quantity from OrderItems where quantity = 100 union all select prod_id,quantity from OrderItems where prod_id like 'BNBG%' order b...

2024-07-30

0 88

题解 | #返回顾客名称和相关订单号以及每个订单的总价#

select cust_name,order_num, quantity*item_price as OrderTotal from Customers inner join Orders using(cust_id) inner join OrderItems using(order_num) ...

2024-07-30

0 86

题解 | #统计运动会项目报名人数(二)#

import pandas as pd items = pd.read_csv('items.csv') signup = pd.read_csv('signup.csv') merge_si = pd.merge(items,signup,how='left',on='item_id') res ...

2024-07-30

0 107

题解 | #牛客网答题正误总数#

import pandas as pd df = pd.read_csv('nowcoder.csv',delimiter=',') print(df.groupby(['result'])['result'].count())

2024-07-30

0 106

题解 | #牛客网每日正确与错误的答题次数#

import pandas as pd df = pd.read_csv('nowcoder.csv',delimiter=',') df['year-month-day'] = pd.to_datetime(df['date'],format='%Y-%m-%d').dt.date print(...

2024-07-30

0 97

题解 | #返回订单数量总和不小于100的所有订单的订单号#

SELECT order_num FROM OrderItems GROUP BY order_num HAVING SUM(quantity) >=100 # WHERE 不能用聚合函数，HAVING中没有分组的列出现时必须使用聚合函数 ORDER BY order_num

2024-07-29

0 102

题解 | #检索供应商名称#

SELECT vend_name FROM Vendors where vend_state = 'CA' and vend_country = 'USA' # SQL中的等于就是=没有赋值符号

2024-07-29

0 101

题解 | #牛客网的每日练题量#

import pandas as pd df = pd.read_csv('nowcoder.csv',delimiter=',',dtype=object) df['date'] = pd.to_datetime(df['date'],format='%Y-%m-%d') dec = df[df...

2024-07-29

1 111

题解 | #将用户的json文件转换为表格形式#

import pandas as pd df = pd.read_json('Nowcoder.json',orient='records',dtype=False) # 不指定dtype的话，Id会变成int类型 # True（默认值）：Pandas将自动推断每列的数据类型。 # False：P...

2024-07-29

0 135

题解 | #统一最后刷题日期的格式#

import pandas as pd df = pd.read_csv('Nowcoder.csv',sep=',',dtype=object) pd.set_option('display.width', 300) # 设置字符显示宽度 pd.set_option('display.max_r...

2024-07-29

0 90