連接列值的更好方法

我有一個具有以下結構和範例數據的表：

create table CUSTOMER_TEST
(
 customer_num Number,
 rel_one      Number,
 rel_two      Number,
 rel_three    Number,
 rel_four     Number
)

  Customer_num    Rel_one     Rel_two        Rel_three        Rel_four 
--------------- ----------- -------------  --------------  --------------
   1               7           12             1000               5
   2               2            1               0                12
   3              12           99              13                0

期望的結果是這樣的：

  Customer_num    Rel_one     Rel_two        Rel_three        Rel_four      Relation_Code
--------------- ----------- -------------  --------------  --------------  ***************
   1               7           12             1000               5           L07R12C99S05
   2               2            1               0                12          L02R01C00S12
   3              12           99              13                0           L12R99C13S00

我寫的是這樣的：

select   customer_num,
        rel_one , 
        rel_two,
        rel_three,
        rel_four,
      'L' ||
      case 
        when   rel_one > 99 then '99'
          else lpad(  rel_one,2,0) end ||
      'R' ||
      case
        when   rel_two > 99 then '99'
          else lpad(  rel_two,2,0) end ||
      'C' ||
       case
        when   rel_three > 99 then '99'
          else lpad(  rel_three,2,0) end  || 
       'S' ||
               case
                when   rel_four > 99 then '99'
                  else lpad(  rel_four,2,0) end as relation_code            
                 
from customer_test ;

有人有更好的主意嗎？而不是使用這麼多的案例陳述..

提前致謝

select   customer_num,
        rel_one , 
        rel_two,
        rel_three,
        rel_four,
      'L' || lpad(LEAST(rel_one,   99), 2, 0) ||
      'R' || lpad(LEAST(rel_two,   99), 2, 0) ||
      'C' || lpad(LEAST(rel_three, 99), 2, 0) ||
      'S' || lpad(LEAST(rel_four,  99), 2, 0)  as relation_code                  
from customer_test ;

我希望 none 值可以為 NULL 或負數。

引用自：https://dba.stackexchange.com/questions/314250