Oracle数据库如何获取当前自然周,当前周的起始和结束日期

SELECT to_char(sysdate,'iw')   from dual; --本周是第几个自然周

SELECT to_char(sysdate,'yyyy') into v_sbzq_nf from dual;  -- 当前年份

SELECT to_char(TRUNC(TO_DATE(to_char(sysdate,'yyyy-MM-dd'),'yyyy-MM-dd'),'IW'),'yyyy-MM-dd')  FROM DUAL;--本周的起始时间（本周周一日期）

SELECT to_char(TRUNC(TO_DATE(to_char(sysdate,'yyyy-MM-dd'),'YYYY-MM-DD'),'IW') + 6,'yyyy-MM-dd') FROM DUAL;--本周的结束时间（本周周日日期）

create or replace procedure PRC_T_SJSB_ZYGYPJG is

   v_sbzq_zs varchar2(20);--上报周期周数

   v_sbzq_nf varchar2(10); --上报周期年份

   v_start varchar2(10);  --起始月份

   v_end varchar2(10);  --结束月份

   v_sbzq varchar2(20); --上报周期

begin

   SELECT to_char(sysdate,'iw') into  v_sbzq_zs from dual; --本周是第几个自然周

   SELECT to_char(sysdate,'yyyy') into v_sbzq_nf from dual;

   SELECT to_char(TRUNC(TO_DATE(to_char(sysdate,'yyyy-MM-dd'),'yyyy-MM-dd'),'IW'),'yyyy-MM-dd') into v_start  FROM DUAL;--本周的起始时间（本周周一日期）

   SELECT to_char(TRUNC(TO_DATE(to_char(sysdate,'yyyy-MM-dd'),'YYYY-MM-DD'),'IW') + 6,'yyyy-MM-dd') into v_end  FROM DUAL;--本周的结束时间（本周周日日期）

   v_start:=substr(v_start,6);

   v_end :=substr(v_end,6);

   v_start :=replace(v_start,'/','.');

   v_start :=replace(v_start,'-','.');

   v_end :=replace(v_end, '/','.');

   v_end :=replace(v_end, '-','.');

   v_sbzq :=v_sbzq_nf||'年第'||v_sbzq_zs||'周';

   insert into T_SJSB_ZYGYPJG (sbzq,sbzt,startdate,enddate) values(v_sbzq,'0',v_start,v_end);
  
   commit;

end PRC_T_SJSB_ZYGYPJG;

select to_char(created_time,'yyyymmdd') as day,count(mobile_no)
from table
where to_char(created_time,'yyyymmdd') >= 20181201
group by to_char(created_time,'yyyymmdd')
order by min(created_time) asc

select to_char(created_time,'iw') as week, min(created_time), count(mobile_no)
from table
where to_char(created_time,'yyyymmdd') >= 20181201
group by to_char(created_time,'iw')
order by min(created_time) asc

select to_char(created_time,'yyyymm') as Month, count(mobile_no)
from table
where to_char(created_time,'yyyymm') >= 20181201
group by to_char(created_time,'yyyymm')

select to_char(created_time,'q') as q,count(mobile_no)
from table
where to_char(created_time,'yyyymmdd') >= 20180101
group by to_char(created_time,'q')
order by min(created_time) asc

select to_char(created_time,'yyyy') as y, count(mobile_no)
from table
where to_char(created_time,'yyyy') >= 2016
group by to_char(created_time,'yyyy')
order by y asc