Issue with Merge

Question

Hi all,
Facing an issue with merge statement. I am getting source rows like:
Table a: (Source)
Id Vald_date Server_serial system_id
1 11/oct/10 2.5 Real Id
1 13/oct/10 2.5
table b: (Target)
Id Vald_date Server_serial system_id
1 13/oct/10 2.5
I am using the below Merge stmt .
MERGE INTO b
USING ( SELECT DISTINCT id,vald_date,server_serial,system_id
from b
ON ( a.Id = b.ID)
when matched then
update set
b.Vald_date = a.Vald_date,
b.server_serial = a. server_serial ,
b.system_id = a.system_id
when not matched then
INSERT values(a.id,a.Vald_date,a. server_serial ,a.system_id
Here , When i run the stmt first time , target table updated with the first source of a table and SQL%ROWCOUNT return 2 rows.
For the second , if we run the same , it is throwing error 'ORA-30926: unable to get a stable set of rows in the source tables'.
Please tell me the cause why it is happening like that and i'm not sure how it is reading and process the rows itself.
Table scripts:
create table a
(id NUMBER,
vald_date DATE,
server_serial NUMBER,
system_id varchar2(10)
Insert into a values(1,TO_DATE('11/OCT/10','DD/MON/YY'),2.5,'Real Id')
Insert into a values(1,TO_DATE('13/OCT/10','DD/MON/YY'),2.5,NULL)
create table b
(id NUMBER,
vald_date DATE,
server_serial NUMBER,
system_id varchar2(10)
Insert into b values(1,TO_DATE('13/OCT/10','DD/MON/YY'),2.5,'Real Id')
Oracle Version:
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bi
PL/SQL Release 10.2.0.4.0 - Production
CORE     10.2.0.4.0     Production
TNS for IBM/AIX RISC System/6000: Version 10.2.0.4.0 - Productio
NLSRTL Version 10.2.0.4.0 - Production
Your help would be appreciated !!
Regards,
Vissu......
Edited by: vissu on Oct 29, 2010 5:41 AM
Edited by: vissu on Oct 29, 2010 6:05 AM

Answer 1

As @Dombrooks already said there is a problem with the data. From next time if you could do like the way I have showed it will be much appreciated.
There are quite a few bugs with your code. Until you sort out the rowsource I don't think you will be able to proceed further with the merge statement.
SQL> drop table a;
Table dropped.
SQL> drop table b;
Table dropped.
SQL> create table a
  2  (id NUMBER,
  3  vald_date DATE,
  4  server_serial NUMBER,
  5  system_id varchar2(10)
  6  )
  7  /
Table created.
SQL> Insert into a values(1,TO_DATE('11/OCT/10','DD/MON/YY'),2.5,'Re
  2  /
1 row created.
SQL> Insert into a values(1,TO_DATE('13/OCT/10','DD/MON/YY'),2.5,NUL
  2  /
1 row created.
SQL> create table b
  2  (id NUMBER,
  3  vald_date DATE,
  4  server_serial NUMBER,
  5  system_id varchar2(10)
  6  )
  7  /
Table created.
SQL> Insert into a values(1,TO_DATE('13/OCT/10','DD/MON/YY'),2.5,'Re
  2  /
1 row created.
SQL>
SQL> MERGE INTO b
  2  USING ( SELECT DISTINCT id,vald_date,server_serial,system_id
  3  from b
  4  )
  5  ON ( a.Id = b.ID)
  6  when matched then
  7  update set
  8  b.Vald_date = a.Vald_date,
  9  b.server_serial = a. server_serial ,
10  b.system_id = a.system_id
11  when matched then
12  INSERT values(a.id,a.Vald_date,a. server_serial ,a.system_id
13  );
when matched then
ERROR at line 11:
ORA-00905: missing keyword
SQL>
SQL> ed
Wrote file afiedt.buf
  1  MERGE INTO b
  2  USING ( SELECT DISTINCT id,vald_date,server_serial,system_id
  3  from b
  4  )
  5  ON ( a.Id = b.ID)
  6  when matched then
  7  update set
  8  b.Vald_date = a.Vald_date,
  9  b.server_serial = a. server_serial ,
10  b.system_id = a.system_id
11  when not matched then
12  INSERT values(a.id,a.Vald_date,a. server_serial ,a.system_id
13* )
SQL> /
ON ( a.Id = b.ID)
ERROR at line 5:
ORA-00904: "A"."ID": invalid identifier
SQL> ed
Wrote file afiedt.buf
  1  MERGE INTO b
  2  USING ( SELECT DISTINCT id,vald_date,server_serial,system_id
  3  from a
  4  ) a
  5  ON ( a.Id = b.ID)
  6  when matched then
  7  update set
  8  b.Vald_date = a.Vald_date,
  9  b.server_serial = a. server_serial ,
10  b.system_id = a.system_id
11  when not matched then
12  INSERT values(a.id,a.Vald_date,a. server_serial ,a.system_id
13* )
SQL> /
3 rows merged.
SQL> select * from a;
        ID VALD_DATE SERVER_SERIAL SYSTEM_ID
         1 11-OCT-10           2.5 Real Id
         1 13-OCT-10           2.5
         1 13-OCT-10           2.5 Real Id
SQL> select * from b;
        ID VALD_DATE SERVER_SERIAL SYSTEM_ID
         1 13-OCT-10           2.5 Real Id
         1 13-OCT-10           2.5
         1 11-OCT-10           2.5 Real Id
SQL> MERGE INTO b
  2  USING ( SELECT DISTINCT id,vald_date,server_serial,system_id
  3  from a
  4  ) a
  5  ON ( a.Id = b.ID)
  6  when matched then
  7  update set
  8  b.Vald_date = a.Vald_date,
  9  b.server_serial = a. server_serial ,
10  b.system_id = a.system_id
11  when not matched then
12  INSERT values(a.id,a.Vald_date,a. server_serial ,a.system_id
13  )
14  /
MERGE INTO b
ERROR at line 1:
ORA-30926: unable to get a stable set of rows in the source tables
SQL> select * from v$version;
BANNER
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bi
PL/SQL Release 10.2.0.4.0 - Production
CORE    10.2.0.4.0      Production
TNS for 64-bit Windows: Version 10.2.0.4.0 - Production
NLSRTL Version 10.2.0.4.0 - ProductionRegards
Raj