snake_case.sql

-- UDTF to return a snake-case of a string for column naming purposes 

-- Simply paste this gist into ACS SQL and run it to create the UDTF.

-- Note: I am using library QUSRSYS. I suggest you put it into your own tool library

-- It is a cool example how far you can go with SQL: Have fun - 
-- (C) Niels Liisberg 2021

-- This gist is distributed on an "as is" basis, without warranties 
-- or conditions of any kind, either express or implied.
----------------------------------------------------------------------------------------------
create or replace function qusrsys.snake_case (
   name varchar(128)
)  

returns varchar(128)
 no external action 
set option output=*print, commit=*none, dbgview = *list
begin
    declare temp varchar(128); 
    
    set temp = lower(name);
    set temp = regexp_replace(temp , '[(].*[)]' , '');
    set temp = regexp_replace(temp , '[æ]' , 'ae');
    set temp = regexp_replace(temp , '[ø@]' , 'oe');
    set temp = regexp_replace(temp , '[å]' , 'aa');
    set temp = regexp_replace(temp , '[^a-z0-9]' , ' ');
    set temp = trim(temp); -- Done here if the name has trailing invalid chars 
    set temp = regexp_replace(temp , ' +', '_');
    
    -- Columns names can not begin with a digit 
    if substring(temp , 1 , 1) >= '0' and substring(temp , 1 , 1) <= '9' then 
        set temp = 'x' concat temp;  
    end if;
    return temp; 
    
end;

-- usecase 
values ( qusrsys.snake_case('Saldo beløb'));
values ( qusrsys.snake_case('Saldo ( men uden det her) beløb '));