查找每月的最后一天

function getLastDayOfMonth(year, month) {
  // month参数范围是0-11，需要将输入的月份减1
  var date = new Date(year, month + 1, 0);
  return date.getDate();
}

var year = 2022;
var month = 1; // 2月份，索引为1
var lastDay = getLastDayOfMonth(year, month);
console.log(lastDay); // 输出28

from datetime import datetime, timedelta

def get_last_day_of_month(year, month):
    # 获取下个月的第一天
    next_month = datetime(year, month, 1) + timedelta(days=32)
    # 减去一天，即为当前月的最后一天
    last_day = next_month - timedelta(days=1)
    return last_day.day

year = 2022
month = 2
last_day = get_last_day_of_month(year, month)
print(last_day)  # 输出28

SELECT LAST_DAY('2022-02-01') AS last_day;