oracle - SQL to find upper case words from a column

Question

I have a description column in my table and its values are:

This is a EXAMPLE
This is a TEST
This is a VALUE

I want to display only EXAMPLE, TEST, and VALUE from the description column.

How do I achieve this?

Answer 1

This could be a way:

-- a test case
with test(id, str) as (
select 1, 'This is a EXAMPLE' from dual union all
select 2, 'This is a TEST' from dual union all
select 3, 'This is a VALUE' from dual union all
select 4, 'This IS aN EXAMPLE' from dual
)
-- concatenate the resulting words
select id, listagg(str, ' ') within group (order by pos)
from (
    -- tokenize the strings by using the space as a word separator
    SELECT id,
           trim(regexp_substr(str, '[^ ]+', 1, level)) str,
           level as pos           
      FROM test t
    CONNECT BY instr(str, ' ', 1, level - 1) > 0
      and prior id = id
      and prior sys_guid() is not null
    )
-- only get the uppercase words
where regexp_like(str, '^[A-Z]+$')   
group by id

The idea is to tokenize every string, then cut off the words that are not made by upper case characters and then concatenate the remaining words.

The result:

1    EXAMPLE
2    TEST
3    VALUE
4    IS EXAMPLE

If you need to handle some other character as an upper case letter, you may edit the where condition to filter for the matching words; for example, with '_':

with test(id, str) as (
select 1, 'This is a EXAMPLE' from dual union all
select 2, 'This is a TEST' from dual union all
select 3, 'This is a VALUE' from dual union all
select 4, 'This IS aN EXAMPLE' from dual union all
select 5, 'This IS AN_EXAMPLE' from dual
)
select id, listagg(str, ' ') within group (order by pos)
from (
    SELECT id,
           trim(regexp_substr(str, '[^ ]+', 1, level)) str,
           level as pos           
      FROM test t
    CONNECT BY instr(str, ' ', 1, level - 1) > 0
      and prior id = id
      and prior sys_guid() is not null
    )
where regexp_like(str, '^[A-Z_]+$')   
group by id

gives:

1   EXAMPLE
2   TEST
3   VALUE
4   IS EXAMPLE
5   IS AN_EXAMPLE