RE: SQL queries

Lee,  

The +0 looks bizarrely like the old trick to stop indexes being used though it would appear that here you wouldn't want to do this. Have you got the explain plans and what version is it?  

Iain Nicoll

-----Original Message-----
Sent: Tuesday, March 12, 2002 4:24 PM
To: Multiple recipients of list ORACLE-L

All,  

Following SQL runs for ages (almost 2 hours)  

select * from table1 addr,
table2 pers,
table3 lookup
table4 cust
where cust.customer_key = lookup_customer_key and lookup_address_key = addr_address_key and lookup.person_key = pers.person_key
and rownum < 1000;  

when this is changed to  

select /*+ FIRST_ROWS */
ADDR.*,
PERS.*,
LOOKUP.*,
CUST.*
from table4 cust,
table2 pers,
table3 lookup
table1 addr
where cust.customer_key = lookup.customer_key + 0 and lookup.address_key = addr.address_key and pers.person_key = lookup.person_key + 0 and rownum < 1000;  

this runs instantaneously. I realise that 99.99% of the improvement is down to the first_rows hint BUT, why does the SQL tool use the list of table aliases with .* after it AND what on earth are the + 0s' on two lines of the predicate list.  

Confused  

Lee  

PS. The Tool is SQLExpert brought to you by those nice blokes at cool-tools
(Cheers Mark Leith !!) and is proving absolutely priceless here at the
moment.    

TIA   The information contained in this communication is confidential, is intended only for the use of the recipient named above, and may be legally privileged. If the reader of this message is not the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please re-send this communication to the sender and delete the original message or any copy of it from your computer system.

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Author: Nicoll, Iain (Calanais)
  INET: iain.nicoll_at_calanais.com

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