GATEverse — GATE CSE previous year questions

Consider the relation account (customer, balance) where the customer is a primary key and there are no null values. We would like to rank customers according to decreasing balance. The customer with the largest balance gets rank $1.$ Ties are not broke but ranks are skipped: if exactly two customers have the largest balance they each get rank $1$ and rank $2$ is not assigned. $\text{Query1:}$ select A.customer, count(B.customer) from account A, account B where A.balance <=B.balance group by A.customer $\text{Query2:}$ select A.customer, 1+count(B.customer) from account A, account B where A.balance < B.balance group by A.customer Consider these statements about Query $1$ and Query $2.$ Which two of the above statements are correct? $2$ and $5$ $1$ and $3$ $1$ and $4$ $3$ and $5$

(A)

Query $1$ will produce the same row set as Query $2$ for some but not all databases.

(B)

Both Query $1$ and Query $2$ are a correct implementation of the specification

(C)

Query $1$ is a correct implementation of the specification but Query $2$ is not

(D)

Neither Query $1$ nor Query $2$ is a correct implementation of the specification

(E)

Assigning rank with a pure relational query takes less time than scanning in decreasing balance order assigning ranks using ODBC.