Performance with SQL?

Question

I have a table named "abc" which have folowing columns:
fname varchar2(30)
lname varchar2(30)
salary number(10,2)
and has ONLY one index on "fname" column.
There's about 100000 rows in it.
SQL1:
select * from abc
where salary>2000 and fname='PETER';
SQL2:
select * from abc
where fname='PETER' and salary>2000;
Question: Which is fast?
a. same performance
b. SQL2 is faster.
c. SQL1 is faster.

Answer 1

Here are two explain plans. The only difference is the order in the where clause. Notice the two plans are identical.
SQL> explain plan for
  2  select *
  3  from   prd.account_master
  4  where  account_id = 1234567890
  5  and    principal_balance_amt = 12345.67;
Explained.
| Id  | Operation                   |  Name                          | Rows  | Bytes | Cost  |
|   0 | SELECT STATEMENT            |                                |     1 |   948 |     2 |
|*  1 |  TABLE ACCESS BY INDEX ROWID| ACCOUNT_MASTER                 |     1 |   948 |     2 |
|*  2 |   INDEX UNIQUE SCAN         | PK_ACCOUNT_MASTER_ACCOUNT_ID   |  3657K|       |     1 |
Predicate Information (identified by operation id):
   1 - filter("ACCOUNT_MASTER"."PRINCIPAL_BALANCE_AMT"=12345.67)
   2 - access("ACCOUNT_MASTER"."ACCOUNT_ID"=1234567890)
SQL> explain plan for
  2  select *
  3  from   prd.account_master
  4  where  principal_balance_amt = 12345.67
  5  and    account_id = 1234567890
  6  ;
Explained.
| Id  | Operation                   |  Name                          | Rows  | Bytes | Cost  |
|   0 | SELECT STATEMENT            |                                |     1 |   948 |     2 |
|*  1 |  TABLE ACCESS BY INDEX ROWID| ACCOUNT_MASTER                 |     1 |   948 |     2 |
|*  2 |   INDEX UNIQUE SCAN         | PK_ACCOUNT_MASTER_ACCOUNT_ID   |  3657K|       |     1 |
Predicate Information (identified by operation id):
   1 - filter("ACCOUNT_MASTER"."PRINCIPAL_BALANCE_AMT"=12345.67)
   2 - access("ACCOUNT_MASTER"."ACCOUNT_ID"=1234567890)