Judgment employee tardiness stored procedure

OR PROCEDURE p_emp_work_detail the REPLACE the CREATE (p_month VARCHAR2) 
the AS 
/ * ************************************** ****************************** 
       program features: create a stored procedure to achieve separate commuting time employees; 
                  determine whether employees are late , leave early, overtime; 
       developer: XXX 
       development time: 2017/09/22 
       source table: ods_emp_work 
       temporary table: temp_emp_work 
       target table: emp_work_detail 
********************* *********************************************** * / 
str VARCHAR2 ( 8000 ); 
the BEGIN
   --- create a temporary table 
  Execute immediate ' Create table temp_emp_work ( 
         U_ID Number ( 20 is  ),
         u_name VARCHAR2 (50),
         u_time varchar2(50),
         sign_in date,
         sign_out date,
         sign_more date
         )';
  
  --给临时表插入数据         
  str:= 'insert into temp_emp_work(u_id,u_name,u_time,sign_in,sign_out,sign_more)
  select u_id,
         u_name,
         to_char(datetime,''yyyymm''),
         max(case when r=1 then datetime else null end) sign_in,
         max(case when r=2 then datetime else null end) sign_out,
         max(case when r=3 then datetime else null end) sign_more
  from(
  select u_id,
         u_name,
         datetime,
         row_number()over(partition by u_id,u_name,to_char(datetime,''yyyymmdd'')order by 1) r
  from ods_emp_work where to_char(datetime,''yyyymm''):=1) 
  group by u_id,
           u_name, 
           TO_CHAR (datetime, the data does not satisfy the working time is updated to empty'' YYYYMM '' ) ' ; 
  the commit;
   - SELECT * from temp_emp_work
   - adjusting Diameter
   - a punch card records
      - a work recorded punch
      - a punch out recording (after 5:00 to commute) 
  Execute immediate ' Update temp_emp_work SIGN_OUT = sign_in SET 
  WHERE SIGN_OUT IS  null and TO_CHAR (sign_in, '' HH24: mi The '' )> '' 1700 '' ' ; 
  -where
  immediate Execute ' Update temp_emp_work = null SET sign_in
     TO_CHAR (sign_in, ' ' HH24: mi The ' ' )> ' ' 1700 ' '' ; 
  the commit;  
   --- three punch card records
       - twice to work, after work time recorded
       - a work twice from work record 
  Execute immediate ' Update temp_emp_work SET SIGN_OUT = sign_more 
  WHERE sign_more IS Not null ' ; 
  the commit;
   - determining whether late, leave early, overtime
   - create the target table
   / * 
  Create table emp_work_detail (   
         U_ID Number (20 is), 
         u_name VARCHAR2 (50), 
         u_month VARCHAR2 (50), 
         sign_in DATE, 
         SIGN_OUT DATE, 
         is_late Number (20),
         is_early number(20),
         is_overtime number(20)
         );
   */
   --给目标表中插入数据
    execute immediate 'truncate table emp_work_detail';
    execute immediate 'insert into emp_work_detail(u_id,u_name,u_month,sign_in,sign_out,is_late,is_early,is_overtime)   
    select u_id,
           u_name,
           substr(u_time,1,6),
           sign_in, 
           sign_out,
           case when to_char(sign_in,''hh24mi'')>''0901''  then 1 else 0 end is_late,
           case when to_char(sign_out,''hh24mi'')<''1730'' then 1 else 0 end is_early,
           case when to_char(sign_out,''hh24mi'')>''2000'' then 1 else 0 end is_over_time
           from temp_emp_work';
    commit;
    execute immediate 'drop table temp_emp_work';
   --select * from emp_work_detail
end;