Top-Down SQL Tuning

Clues 2.1

SELECT DISTINCT O.Order_ID, O.Order_Date, C.Name, L.Quantity, I.Name

FROM Orders O, Order_Lines L, Items I, Customers C

WHERE O.Customer_ID = :B1

AND L.Order_ID = O.Order_ID

AND I.Item_ID = L.Item_ID

AND C.Customer_ID = O.Customer_ID;

.1 SELECT STATEMENT

..2 SORT UNIQUE

...3 NESTED LOOPS

....4 NESTED LOOPS

.....5 NESTED LOOPS

......6 TABLE ACCESS BY INDEX ROWID 4*CUSTOMERS

.......7 INDEX UNIQUE SCAN CUSTOMERS_U1: customer_id

......6 TABLE ACCESS BY INDEX ROWID 1*ORDERS

.......7 INDEX RANGE SCAN ORDERS_N4: customer_id

.....5 TABLE ACCESS BY INDEX ROWID 2*ORDER_LINES

......6 INDEX RANGE SCAN ORDER_LINES_N1: order_id

....4 TABLE ACCESS BY INDEX ROWID 3*ITEMS

.....5 INDEX RANGE SCAN ITEMS_U1: item_id,org_id