oracle查看日期是第几周

╰半橙微兮° 2023-06-24 10:27 99阅读 0赞

https://www.2cto.com/database/201302/191827.html

oracle查看日期是第几周

系统当前时间是多少周,就是是今年的第几个星期

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select to_char(sysdate,’ww’) ,to_char(sysdate,’iw’) from dual;

select to_char(sysdate,’ddd’) from dual;

select TRUNC(SYSDATE,’MM’) from dual;1)

ww的算法为每年1月1日为第一周开始,date+6为每一周结尾

例如:20050101为第一周的第一天,而第一周的最后一天为20050101+6=20050107  

公式: 每周第一天 :date + 周 * 7 - 7  每周最后一天:date + 周 * 7 - 12)

iw的算法为星期一至星期日算一周,且每年的第一个星期一为第一周,

例如:20050101为星期六,所以用iw的算法是前年的53周,而20050103之后才是第一周的开始。  

公式: 每周第一天 :next_day(date) + 周 * 7 - 7每周最后一天:next_day(date) + 周 * 7 - 13)

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其它:  

A、查今天是 “本月” 的第几周  SELECT TO_CHAR(SYSDATE,’WW’) - TO_CHAR(TRUNC(SYSDATE,’MM’),’WW’) + 1 AS “weekOfMon” from dual;  或  SELECT TO_CHAR(SYSDATE,’W’) AS “weekOfMon” from dual;  

B、查今天是 “今年” 的第几周  select to_char(sysdate,’ww’) from dual;  或  select to_char(sysdate,’iw’) from dual;

统计哪年哪个星期的哪一天:

int year=2011;

  1. int week=1;
  2. Calendar calFirstDayOfTheYear = new GregorianCalendar(year,
  3. Calendar.JANUARY, 1);
  4. calFirstDayOfTheYear.add(Calendar.DATE, 7 \* (week-1));
  5. int dayOfWeek = calFirstDayOfTheYear.get(Calendar.DAY\_OF\_WEEK);
  6. Calendar calFirstDayInWeek = (Calendar)calFirstDayOfTheYear.clone();
  7. calFirstDayInWeek.add(Calendar.DATE,
  8. calFirstDayOfTheYear.getActualMinimum(Calendar.DAY\_OF\_WEEK) - dayOfWeek);
  9. Date firstDayInWeek = calFirstDayInWeek.getTime();
  10. System.out.println(year + "年第" + week + "个礼拜的第一天是" + ReportDateUtil.getFromatDay().format(firstDayInWeek));
  11. Calendar calLastDayInWeek = (Calendar)calFirstDayOfTheYear.clone();
  12. calLastDayInWeek.add(Calendar.DATE,
  13. calFirstDayOfTheYear.getActualMaximum(Calendar.DAY\_OF\_WEEK) - dayOfWeek);
  14. Date lastDayInWeek = calLastDayInWeek.getTime();
  15. System.out.println(year + "年第" + week + "个礼拜的最后一天是" + ReportDateUtil.getFromatDay().format(lastDayInWeek));

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