Uppercase and Lowercase Queries

Question

Is there any performance difference if i execute sql statements with mixed case and uppercase. what will be the fastest and why? please explain? THks in advance.
Raj

Answer 1

do we all agree that If oracle has to reparse the statement (that is it is not
found amoung the shared sql) then performance could be adversely affected?
just a thought...have a look at v$sqlarea
from session A as system
SQL> alter system flush shared_pool;
from session b as my user
SQL> SELECT sysdate FROM dual;
from session A as system (find parsing_user_id in dba_users table (user_id))
SQL> SELECT SQL_TEXT FROM V$SQLAREA WHERE PARSING_USER_ID = 28;
SQL_TEXT
SELECT sysdate FROM dual
from session b as my user execute same statement case and all
SQL> SELECT sysdate FROM dual;
from session A as system
SQL> SELECT SQL_TEXT FROM V$SQLAREA WHERE PARSING_USER_ID = 28;
SQL_TEXT
SELECT sysdate FROM dual
from session b as my user
SQL> SELECT SYSDATE FROM DUAL;
from session A as system
SQL> SELECT SQL_TEXT FROM V$SQLAREA WHERE PARSING_USER_ID = 28;
SQL_TEXT
SELECT sysdate FROM dual
SELECT SYSDATE FROM DUAL;
......conclusions?
looks like we now have another copy of our select
did oracle hardparse the 2nd query?