For the following sql query statements: Select Distinct sno, sname From Student, SC Where Student.sno=SC.sno And cno=’C001′ Please use common sense to determine which of the following query plans should be executed most efficiently? (Assuming the SC has a citation on the cno and the Student has an index on the snoo) ()
A.(1) Student and SC are connected on the SNO; (2) make the choice of cno=’C001′ on the result of (1); (3) Project the result of (2) on sno, sname.
B. (1) make the choice of cno=’C001′ on the SC, (2) connect the result of (1) with the Student on the SNO; (3) Project the result of (2) on sno, sname.
C. (1) make the choice of cno=’C001′ on SC, (2) project student on sno, sname, and project the result of (1) on sno; (3) Connect the two results of (2) on the SNO.
D. (1) make a choice of cno=’C001′ on SC, (2) project the result of (1) on sno; (3) Connect the result of (1) with Student on the SNO; (4) Project the result of (3) on sno, sname.
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