Limit Characters Returned in Oracle SQL Query

How to limit the amount of characters returned in Oracle query

If I understood what you are saying, SUBSTR returns only a portion of some string, so that would be

select substr(your_string, 1, 32760)
from ...

How do I limit the number of rows returned by an Oracle query after ordering?

You can use a subquery for this like

select *
from  
( select * 
  from emp 
  order by sal desc ) 
where ROWNUM <= 5;

Have also a look at the topic On ROWNUM and limiting results at Oracle/AskTom for more information.

Update:
To limit the result with both lower and upper bounds things get a bit more bloated with

select * from 
( select a.*, ROWNUM rnum from 
  ( <your_query_goes_here, with order by> ) a 
  where ROWNUM <= :MAX_ROW_TO_FETCH )
where rnum  >= :MIN_ROW_TO_FETCH;

(Copied from specified AskTom-article)

Update 2:
Starting with Oracle 12c (12.1) there is a syntax available to limit rows or start at offsets.

SELECT * 
FROM   sometable
ORDER BY name
OFFSET 20 ROWS FETCH NEXT 10 ROWS ONLY;

See this answer for more examples. Thanks to Krumia for the hint.

Oracle SQL Developer limit number of character of datatype char(5)

Your regex ^[A-Z]{2}[0-9]$ only allows (exactly) three characters. But a column defined as char(5) gets padded with spaces if you provide less than three, so in reality 'AA1' will be stored as 'AA1 ' which violates your regex.

Use char(3) instead.

Better yet, never use char at all (you just experienced one of the reasons why), use varchar(5) or varchar(3) both will work with your regex.

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2 or 4 uppercase letters plus 1 digit whose value is between 1 and 4

That's not what your regex does. [A-Z]{2} is exactly two uppercase letters. If you want to allow patterns of different lengths there is no way you can use char(5) unless you also include the spaces in the regex:

create table test
(
  groupcode char(5) check(
      regexp_like(groupcode, '(^[A-Z]{2}[0-9]  $)|(^[A-Z]{4}[0-9]$)', 'c'))
);

The above regex allows two uppercase characters followed by on digit and two spaces or four uppercase characters followed by one digit.

LISTAGG 4000 Character Limit - Result of string concatenation is too long

The best solution I know is posted somewhere in the Internet... You could probably just google for it. It basically consist of few steps:

1. Creating a collection type to store each text value to concatenate

create or replace type string_array_t as table of VARCHAR2(4000);

2. Creating a PL/SQL function which takes string_array_t as parameter and returns concatenated text as CLOB:

create or replace function 
  string_array2clob(
    p_string_array string_array_t
    ,p_delimiter varchar2 default ','
) RETURN CLOB IS
  v_string CLOB;
BEGIN
  -- inside is a loop over p_string_array to concatenate all elements
  --
  -- below is just a draft because in real you should use a while loop
  -- to handle sparse collection and you should put some checks to handle not initialized collection
  -- and other important cases
  -- furthermore it's better to create additional varchar2 variable as a buffer
  -- and convert that buffer to clob when it's full for a better performance
  for indx in p_string_array.first..p_string_array.last loop
    v_string := v_string || to_clob(p_string_array(indx) || p_delimiter);
  end loop;

  RETURN substr(v_string, 1, nvl(length(v_string),0) - nvl(length(p_delimiter),0));
END string_array2clob;
/

3. Aggregate query as usual but using cast and collect instead of listagg and at the end convert it to clob with function from step above:

select t.name, string_array2clob(cast(collect(t.text order by t.line) as string_array_t ), p_delimiter => chr(10)) as text
   from user_source t 
  group by t.name;

If your query is not just an example of concept and really you're trying to get a source of some object in database, then you should read about dbms_metadata.get_ddl function. It's made for it.

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