rownum and group by to limit to 1000 rows in detail - oracle

Question

I need to limit to 1000 rows in detail table EL8_STGG_CEHL_EXCP for each unique combination keys(AST_ID,PRCS_ID,PRCS_NME,PRCS_STEP_NME,SRC_APPL_LOG_DT) in the EL8_STGG_CEHL_LOG.
For example - If there are 3 unique combination keys, I expect 3000 rows in the detail table.
SELECT
E.AST_ID,
E.PRCS_ID,
E.PRCS_NME,
E.PRCS_STEP_NME,
E.SRC_APPL_LOG_DT
FROM EL8_STGG_CEHL_EXCP E,EL8_STGG_CEHL_LOG L
WHERE
L.AST_ID = E.AST_ID
AND L.PRCS_ID = E.PRCS_ID
AND L.PRCS_NME = E.PRCS_NME
AND L.PRCS_STEP_NME = E.PRCS_STEP_NME
AND L.SRC_APPL_LOG_DT = E.SRC_APPL_LOG_DT
AND (L.CEHL_PICK_UP_IND IS NULL OR UPPER(L.CEHL_PICK_UP_IND) not in ('Y','P'))
GROUP BY
E.AST_ID,
E.PRCS_ID,
E.PRCS_NME,
E.PRCS_STEP_NME,
E.SRC_APPL_LOG_DT
it would be great help if anyone can help me out
Thanks

Answer 1

Untested... that's a lot of data to mock up.
Basically, I use my favorite analytic function, row_number()
with limited as (
select
L.*,
row_number() over (partition by AST_ID,PRCS_ID,PRCS_NME,
PRCS_STEP_NME,SRC_APPL_LOG_DT order by rownum) as rn
from EL8_STGG_CEHL_LOG L
)
SELECT
E.AST_ID,
E.PRCS_ID,
E.PRCS_NME,
E.PRCS_STEP_NME,
E.SRC_APPL_LOG_DT
FROM
EL8_STGG_CEHL_EXCP E,
limited L
WHERE
L.AST_ID = E.AST_ID
AND L.PRCS_ID = E.PRCS_ID
AND L.PRCS_NME = E.PRCS_NME
AND L.PRCS_STEP_NME = E.PRCS_STEP_NME
AND L.SRC_APPL_LOG_DT = E.SRC_APPL_LOG_DT
AND L.RN <= 1000
AND (L.CEHL_PICK_UP_IND IS NULL OR UPPER(L.CEHL_PICK_UP_IND) not in ('Y','P'))