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Oracle Q in Java Interview
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prat de
Greenhorn
Joined: Sep 15, 2003
Posts: 22
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Hi everybody,
please share your opinions/answer regarding foll. oracle q:
There are two tables, customer and order tables:
Customer
CustomerID CustomerName Phone
Order
OrderID CustomerID Orders
Query:
Select Customer.CustomerID, Order.OrderID, Order.Orders, Customer.CustomerName from Customer, Order
where CustomerID >=1000;
Which part of the query will take maximum time of execution?
- prat.
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SJ Adnams
Ranch Hand
Joined: Sep 28, 2001
Posts: 925
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looks like a cartesian join to me...
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D. Rose
Ranch Hand
Joined: Apr 25, 2003
Posts: 215
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MAximum time of the query will be spent in scanning Orders table as it will be full table scan for that table.
Changing where clause to " where customer.customerId >=1000 and order.customerId=customer.customerId" will avoid this full scan.
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subject: Oracle Q in Java Interview
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