Strange in this sql query , kindly help

Question

I have aqry with ed_eff_m as some value and ed_end_m as NULL. I am replaing the NULL with sysdate. BOTH columns are TIMESTAMP
subquery :
SELECT MAX(ED_EFF_M),MAX(NVL(ED_END_M,SYSDATE))
FROM AUDIT_GRN ag2
where ag2.grn_n=281421
This is giving two dates.
when i execute another sql on top of this with the same condition, its not giving any result. (the same table and the same condition is used)
SELECT OPT_WA_FAIR_VAL_A
FROM AUDIT_GRN ag
WHERE ag.GRN_N = 281421
AND (ag.ED_EFF_M,NVL(ag.ED_END_M,SYSDATE)) IN
SELECT MAX(ED_EFF_M),MAX(NVL(ED_END_M,SYSDATE))
FROM AUDIT_GRN ag2
WHERE ag2.grn_n=ag.grn_n
)

Answer 1

Hello, thanks for your reply.
There is only one record which ed_eff_m = 04-Aug-2006 and Ed_END_M AS NULL.
I am replacing the null with sysdate. I am getting the result with the subquery
SELECT to_char(MAX(ED_EFF_M)),to_char(MAX(NVL(ED_END_M,SYSDATE)))
FROM AUDIT_GRN ag2
WHERE ag2.grn_n=281421
04-AUG-06 12.24.13.764450 PM 17-AUG-06 12.57.59.000000 PM
when i run the same query on top of this using IN clause, i should get the same result but its not ginving it. I am not using any other condition.
SELECT OPT_WA_FAIR_VAL_A, ag.ED_EFF_M,NVL(ag.ED_END_M,SYSDATE)
FROM AUDIT_GRN ag WHERE ag.GRN_N = 281421
AND (to_char(ag.ED_EFF_M),to_char(NVL(ag.ED_END_M,SYSDATE))) IN (
SELECT to_char(MAX(ED_EFF_M)),to_char(MAX(NVL(ED_END_M,SYSDATE)))
FROM AUDIT_GRN ag2
WHERE ag2.grn_n=281421)
It should give me the same row, since the first query and second query is giving output when i execute it seperatly