Oracle SQL查询仅选择部门表上日期最早的记录

Question

如果同一部门记录的“Login_Date”列的时间差在18小时内，则只选择最早登录日期的记录。

以下是抽样数据：

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需要查询以下数据：

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Answer 1

试试这个：

Select Record_ID,d.Department,User,d.Login_Date
from data d
inner join ( Select Department,min(Login_Date) 
             from data 
             where EXTRACT(HOUR FROM CAST(Login_Date AS timestamp)) <= 18
             group by Department,trunc(Login_Date) ) as t
on d.Department= t.Department and d.Login_Date = t.Login_Date