RE: SQL queries

[Mark Leith]

Cheers Lee! One up for the "bad guys"! ;P

-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Robertson Lee - lerobe
Sent: 12 March 2002 16:24
To: Multiple recipients of list ORACLE-L
Subject: SQL queries

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

 



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