select

SELECT
t.orderid,
RTRIM(
XMLAGG(
XMLELEMENT(e, chunk_content).EXTRACT('//text()')
ORDER BY chunk_num
).getclobval()
) AS full_text
FROM ZEXECUTION t
CROSS JOIN (
SELECT
LEVEL AS chunk_num,
(LEVEL * 4000 - 3999) AS start_byte,
(LEVEL * 4000) AS end_byte
FROM dual
CONNECT BY LEVEL <= CEIL(
blob_length(t.UNDINSTRMTGRP) / 4000
)
) c
WHERE t.orderid = '2524650mm1x'
AND blob_to_text_range(
t.UNDINSTRMTGRP,
c.start_byte,
c.end_byte
) IS NOT NULL
GROUP BY t.orderid;