Derived Relations

1. SQL-92 allows a subquery expression to be used in the from clause.
2. If such an expression is used, the result relation must be given a name, and the attributes can be renamed.
3. Find the average account balance of those branches where the average account balance is greater than $1,000.

    select bname, avg-balance
   
   		 from (select bname, avg(balance)
   
   		 		 		 from account
   
   		 		 		 group by bname)
   
   		 		 		 as result(bname, avg-balance)
   
   		 where avg-balance > 1000
   
   

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