Consider the following three SQL queries (Assume the data in the people table):
(a)Select Name from people where Age > 21;
(b)Select Name from people where Height > 180;
(c)Select Name from people where (Age > 21) or (Height > 180);
If the SQL queries (a) and (b) above, return 10 rows and 7 rows in the result set respectively, then what is one possible number of rows returned by the SQL query (c) ?

(A) 3
(B) 7
(C) 10
(D) 21


Answer: (C)

Explanation: According to question:
Select Name from people where Age > 21; will return 10 rows.
Select Name from people where Height > 180; will return 7 rows.
Then Select Name from people where (Age > 21) or (Height > 180); will return 10 rows. Since there is or between the condition. That’s why it will return 10 rows.
So, option (C) is correct.


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