QUESTION 8 Given table R(A,B,C) and S(C,D,E), which of the following SQL stateme

Question

QUESTION 8

Given table R(A,B,C) and S(C,D,E), which of the following SQL statements would find the record(s) with null values on the column C in table R?

a.   select * from R left outer join S where R.C = S.C;

b.   select * from R right outer join S where R.C = S.C;

c.   either a. or b.

d.   neither a. nor b.

QUESTION 20

Given table R(A,B,C) and S(C,D,E), which of the following SQL statements would find the record(s) with null values on the column C in table S?

a.   select * from R left outer join S where R.C = S.C;

b.   select * from R right outer join S where R.C = S.C;

c. either a. or b.

d.   neither a. nor b.

Explanation / Answer

Join clause is used to combine the rows from two or more tables based on a related or common column between them which contains unique value except null value. You can perform join query on any other column of the table which don't contain any null value. Assuming given tables i.e R and S contain any common value column then perform left outer join between R and S to find records with null values on column C in table R and right outer join between R and S to find same on column C in table S.

Left outer join will returns all records from left table and matched records from right table.

Right outer join will returns all the records from right table and matched records from left table.

So, answer of both questions is d. i.e. neither a nor b

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