杭州银行 笔试彻底凉了...

📍 笔试公司：杭州银行

💻 笔试岗位：科技岗

📚 笔试问题：

计算机基础+1道sql题+1道Python题+数据分析题+日常情况了解。

2道手撕都不会...身心俱疲了.........

但还是尽量记录一下给uu们吧。

1. hdfs edits log和fsimage分别记录什么？
2. sql exist和in哪个快一些？
3. Python class中__dict__是什么？

sql，求2024年交易次数至少10次的用户名、交易次数、交易总金额、交易类型，按照交易次数降序排序。

我死也记不清如何获得像id,customer_id,transaction_type的情况如何获得每个customer_id出现次数最多的transaction_type了。现在我要记录下来，都需要用到窗口函数，以下来自大模型。

法一：

WITH TransactionCount AS (
    SELECT
        customer_id,
        transaction_type,
        COUNT(*) AS transaction_count
    FROM
        transaction_table
    GROUP BY
        customer_id,
        transaction_type
),
RankedTransactions AS (
    SELECT
        customer_id,
        transaction_type,
        transaction_count,
        ROW_NUMBER() OVER (PARTITION BY customer_id ORDER BY transaction_count DESC) AS rn
    FROM
        TransactionCount
)
SELECT
    customer_id,
    transaction_type,
    transaction_count
FROM
    RankedTransactions
WHERE
    rn = 1;

法二：

SELECT
    customer_id,
    transaction_type,
    transaction_count
FROM (
    SELECT
        customer_id,
        transaction_type,
        COUNT(*) AS transaction_count,
        MAX(COUNT(*)) OVER (PARTITION BY customer_id) AS max_transaction_count
    FROM
        transaction_table
    GROUP BY
        customer_id,
        transaction_type
) AS subquery
WHERE
    transaction_count = max_transaction_count;

算法题：翻转链表，要求用Python实现。要求前一半翻转，然后后一半也翻转。

例如[1,2,3,4,5]翻转为[2,1,5,4,3]；[1,2,3,4]翻转为[2,1,4,3]。