[날짜함수] employee 테이블에서 6개월 후 첫 월요일에 연봉협상 일정을 잡으려고 할 때, 그 날짜를 구해주세요.

1. oracle

1)

select next_day(add_months(hire_date,6),'월요일') from employees;

2)

select next_day(hire_date + to_yminterval('0-6'),'월') from employees;

<참고>

-- select next_day(add_months(sysdate,6),'월요일') from dual;

-- select next_day(sysdate + to_yminterval('0-6'),'월') from dual;

2. r

library(lubridate)

add <- 8 - as.numeric(format(as.Date(emp$HIRE_DATE) + months(6),'%w'))

as.Date(emp$HIRE_DATE) + months(6) + days(add)

#검증 : weekdays(as.Date(emp$HIRE_DATE) + months(6) + days(add))

3. python

import pandas as pd

import datetime

import dateutil

emp=pd.read_csv("c:/data/employees.csv")

emp['HIRE_DATE']=[datetime.datetime.strptime(i,'%Y-%m-%d') for i in emp['HIRE_DATE']]

emp['6MONTH']=[i+dateutil.relativedelta.relativedelta(months=6) for i in emp['HIRE_DATE']]

x = [8-i.weekday() for i in emp['6MONTH']]

res=[]

for i in range(len(emp['6MONTH'])):

    res.append(emp['6MONTH'][i] + dateutil.relativedelta.relativedelta(days=x[i]))

print(res)