Oracle SQL : Retrieving non-existing values from IN clause

Question

Having following query:

select table_name
from user_tables
where table_name in (\'A\',\'B\',\'C\',\'D\',\'E\',\'F\');

Assuming only user_tables

Answer 1

Are you restricted to receiving those values as a comma delimited list?

1. instead of creating a comma delimited list with the source values, populate an array (or a table).
2. pass the array into a pl/sql procedure (or pull a cursor from the table).
3. loop through the array(cursor) and use a dynamic cusror to select count(table_name) from user_tables where table_name = value_pulled.
4. insert into table B when count(table_name) = 0.

5. then you can select all from table B

   select * from tab1;
   ------------------
   A
   B
   C
   D 
   E
   F 
   
   Create or replace procedure proc1 as  
   
   cursor c is select col1 from tab1;
   r tab1.col1%type;
   i number;
   
   begin  
   
   open c;
   loop
     fetch c into r;
     exit when c%notfound; 
     select count(tname) into i from tab where tname = r;
       if i = 0 then 
         v_sql := 'insert into tab2 values ('''||r||''');
         execute immediate v_sql; 
         commit;
       end if; 
   end loop;
   close c;
   end proc1;
   
   select * from tab2;
   ------------------
   A
   D 
   E 
   

if this is not a one-off, then having this proc on hand will be handy.