FInding missing sequence number

Question

Dear All
I have a column in table like this (actually its just a sample):
TAB
MMxxxx9988
MMxxxx9990
MMxxxx9995
MMxxxx9998
MMxxxx9999
MMxxxx0000
MMxxxx0001
MMxxxx0003
MMxxxx0004
MMxxxx0005
MMxxxx0008
xxxx is variable
last four digit is a sequence number start with 0000 and end with 9999.
when the last four digit exceeds 9999 it reset to 0000
My question is : how can we find the missing sequence number for that column.
example:
for the above table , it should give the below result:
TAB
MMxxxx9989
MMxxxx9991
MMxxxx9992
MMxxxx9993
MMxxxx9994
MMxxxx9996
MMxxxx9997
MMxxxx0002
MMxxxx0006
MMxxxx0007
Thanks

Answer 1

One another way of doing it:
For ease of verification, I have removed the records from 0001 to 9988.
with data as
  select 'MMxxxx9988' col from dual union all
  select 'MMxxxx9990' col from dual union all
  select 'MMxxxx9995' col from dual union all
  select 'MMxxxx9998' col from dual union all
  select 'MMxxxx9999' col from dual
--  select 'MMxxxx0000' col from dual union all
--  select 'MMxxxx0001' col from dual union all
--  select 'MMxxxx0003' col from dual union all
--  select 'MMxxxx0004' col from dual union all
--  select 'MMxxxx0005' col from dual union all
--  select 'MMxxxx0008' col from dual
select distinct col, nxt_val, substr(col, 1, 6) || to_char(st_with + level, 'fm00009') miss_seq
  from (
        select col, nxt_val, col_num st_with, nxt_col_num end_with
          from (
                select col, lead(col) over (partition by substr(col, 1, 6) order by substr(col, -4, 4)) nxt_val,
                       to_number(substr(col, 7, 4)) col_num, to_number(substr(lead(col) over (partition by substr(col, 1, 6) order by substr(col, -4, 4)), 7, 4)) nxt_col_num
                  from data
         where abs(col_num - nxt_col_num) > 1
connect by level <= (end_with - st_with) - 1
   and prior col = col
   and prior sys_guid() is not null
order by col;
COL        NXT_VAL    MISS_SEQ    
MMxxxx9988 MMxxxx9990 MMxxxx09989 
MMxxxx9990 MMxxxx9995 MMxxxx09991 
MMxxxx9990 MMxxxx9995 MMxxxx09992 
MMxxxx9990 MMxxxx9995 MMxxxx09993 
MMxxxx9990 MMxxxx9995 MMxxxx09994 
MMxxxx9995 MMxxxx9998 MMxxxx09996 
MMxxxx9995 MMxxxx9998 MMxxxx09997 
7 rows selected