Query optimisation?

[drkestrel]

I need to run a query the contents of two identical tables on two DB schemas, whose ORACLE_SID are set to set1 and set2

questions-
1) If I set ORACLE_SID to set1 on UNIX command prompt and lauch SQL Plus, how could I refer to table1 in set2?

2) There are many fields in the table, and I need to run a query of format
(Syntax is incorrect)

select * from table1 where table1.pk=set2.table1.pk AND table1.field1<>set2.table1.field1 AND table1.field2<>set2.table1.field2 AND 
table1.field3<>set2.table1.field3 AND 
etc etc.

Could this query by optimized to speed things up a bit??

 

[kindus]

Few things,
1) multiple schemas can reside in a single oracle database (ORACLE_SID).
If that is the case, you may refer your tables e.g. as
select t1.col1,t2.col1
from s1.table1 t1, s2.table1 t2
where t1.key_col=t2.key_col;

2) if you schemas are in two different databases, then you need to create a database link in the database where you want to execute your query linking to the second database.After that statement should be something like this

select s1.col1,s2.col1
from s1.table1 t1, s2.table1@dblink t2
where t1.key_col=t2.key_col;

Lastly, for any suggestion on optimization you may post your final query.

Hope it helps