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Tag: optimization

Why does this suggested solution prefer a different way of calculating percentages based on aggregations?

I’m working through a problem set from CMU’s public db systems course. I have the following two tables: Order Id CustomerId EmployeeId OrderDate RequiredDate ShippedDate ShipVia Freight ShipName ShipAddress ShipCity ShipRegion ShipPostalCode ShipCountry 10248 VINET 5 2012-07-04 2012-08-01 2012-07-16 3 16.75 Vins et alcools Chevalier 59 rue de l’Abbaye Reims Western Europe 51100 France 10249 TOMSP 6 2012-07-05 2012-08-16 2012-07-10

Syntax performance of INNER JOIN

Is the performance of both these examples the same? Example 1: Example 2: I am using example #2 at the moment since I am joining 15+ tables, each table with many unnecessary columns and many rows (1 million+) Answer Oracle is smart enough and does not take all columns from table 1 and join them with all columns from table