Oracle 11g Release 2

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create table salarymaster 
as
select 10001 EMPID, 12000 SALARY from dual union all
select 10002,   60000 from dual union all
select 10003,   25000 from dual union all
select 10004,   35000 from dual union all
select 10005,   15000 from dual union all
select 10006,   24000 from dual union all
select 10007,   85000 from dual union all
select 10008,   75000 from dual union all
select 10009,   65000 from dual union all
select 10010,   67000 from dual union all
select 10011,   95000 from dual union all
select 10012,   23000 from dual union all
select 10013,   48000 from dual union all
select 10014,   25000 from dual union all
select 10015,   35000 from dual ;
15 rows affected

create table currentsalaries
as
select 10001 EMPID,  24000 SALARY from dual union all
select 10002,   60000 from dual union all
select 10003,   36000 from dual union all
select 10004,   35000 from dual union all
select 10005,   23000 from dual union all
select 10006,   24000 from dual union all
select 10007,   99000 from dual union all
select 10008,   75000 from dual union all
select 10009,   79000 from dual union all
select 10016,   52000 from dual union all
select 10017,   98000 from dual union all
select 10018,   63000 from dual union all
select 10019,   77000 from dual union all
select 10020,   47000 from dual union all
select 10021,   35000 from dual ;
15 rows affected

create table mergelog
as
select empid, salary, 'unchanged' as status
from salarymaster ;
15 rows affected

merge into mergelog M
using
  currentsalaries C
  on ( M.empid = C.empid )
when matched then
  update set 
    M.salary = C.salary
  , M.status = 'UPDATED'
  where M.salary <> C.salary
when not matched then
  insert ( M.empid, M.salary, M.status )
    values ( C.empid, C.salary, 'INSERTED' )
;
11 rows affected

select * from mergelog order by empid ;


EMPID
SALARY
STATUS


10001
24000
UPDATED

10002
60000
unchanged

10003
36000
UPDATED

10004
35000
unchanged

10005
23000
UPDATED

10006
24000
unchanged

10007
99000
UPDATED

10008
75000
unchanged

10009
79000
UPDATED

10010
67000
unchanged

10011
95000
unchanged

10012
23000
unchanged

10013
48000
unchanged

10014
25000
unchanged

10015
35000
unchanged

10016
52000
INSERTED

10017
98000
INSERTED

10018
63000
INSERTED

10019
77000
INSERTED

10020
47000
INSERTED

10021
35000
INSERTED

EMPID	SALARY	STATUS
10001	24000	UPDATED
10002	60000	unchanged
10003	36000	UPDATED
10004	35000	unchanged
10005	23000	UPDATED
10006	24000	unchanged
10007	99000	UPDATED
10008	75000	unchanged
10009	79000	UPDATED
10010	67000	unchanged
10011	95000	unchanged
10012	23000	unchanged
10013	48000	unchanged
10014	25000	unchanged
10015	35000	unchanged
10016	52000	INSERTED
10017	98000	INSERTED
10018	63000	INSERTED
10019	77000	INSERTED
10020	47000	INSERTED
10021	35000	INSERTED