SQL Optimizer
- From: Bob Robert <mssql_2002@xxxxxxxxx>
- To: oracle-l@xxxxxxxxxxxxx
- Date: Mon, 10 Sep 2007 08:37:21 -0700 (PDT)
Could you please comment on the following SQL queries between Original
SQL and Modified SQL. It seems that modified SQL's are perfoming better
but I don't know how exactly Oracle optimizer works.
Original Query1:
SELECT *
FROM orders
WHERE orders_updt_dtm BETWEEN sysdate - 7 AND sysdate
/
Modified Query1:
SELECT *
FROM orders
WHERE 7 >= sysdate - orders_last_updt_dtm
/
Original Query2:
SELECT *
FROM sales
WHERE sales_updt_dtm BETWEEN sysdate - 7 AND sysdate
/
Modified Query2:
SELECT *
FROM sales
WHERE sales_updt_dtm >= sysdate - 7 - 0
AND sales_updt_dtm <= sysdate - 0
/
Thanks,
Bob
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