MERGE question

Question

Can you specify more than one condition in the ON clause? In all the examples I've seen there is only an inner join (a.col1=b.col1)? Just curious.
Matt

Answer 1

The another thing to watch - you are not allowed to change columns referenced in the ON clause .That reminded me on the old bug, which seems to be not corrected still - Oracle does allow such updates by merging into the view, the behaviour was broken somewhere after 9.2.0.6.
-- Setup
SQL> create table t1 (n number,text varchar2(10));
SQL> create table t2 (m number,new_text varchar2(10));
SQL> create view v1 as
  2  select * from t1;
SQL> insert into t1 values (1,'a');
SQL> insert into t1 values (2,'b');
SQL> insert into t1 values (3,'c');
SQL> insert into t2 values (1,'d');
SQL> insert into t2 values (2,'e');
SQL> insert into t2 values (3,'f');
SQL> insert into t2 values (101,'g');
SQL> insert into t2 values (102,'h');
SQL> insert into t2 values (103,'i');
-- 9.2.0.8 (on the 9.2.0.6 merge into view raise an ORA-00904
SQL> merge into t1 a
  2  using t2 b on (n=m)
  3  when matched then update
  4  set n = n + 100,text=new_text
  5  when not matched then
  6  insert values(b.m,b.new_text);
using t2 b on (n=m)
ERROR at line 2:
ORA-00904: "N": invalid identifier
SQL>
SQL> merge into v1 a
  2  using t2 b on (n=m)
  3  when matched then update
  4  set n = n + 100,text=new_text
  5  when not matched then
  6  insert values(b.m,b.new_text);
6 rows merged.
-- On 10.2.0.4 and 11.1.0.6.0
SQL> merge into t1 a
  2  using t2 b on (n=m)
  3  when matched then update
  4  set n = n + 100,text=new_text
  5  when not matched then
  6  insert values(b.m,b.new_text);
using t2 b on (n=m)
ERROR at line 2:
ORA-38104: Columns referenced in the ON Clause cannot be updated: "N"
SQL>
SQL> merge into v1 a
  2  using t2 b on (n=m)
  3  when matched then update
  4  set n = n + 100,text=new_text
  5  when not matched then
  6  insert values(b.m,b.new_text);
6 rows merged.Interestingly, Metalink claims that bug (5891015) to be fixed in 11.0 Base Release.
Best regards
Maxim