ACE-FT

Question

if total_sales have all NULL entries then it will return all employee .please clarify.

Comments

@Shubhgupta 

you are right.

This expression of the maximum seems consistent with mathematical logic, but fails completely in SQL:

SELECT DISTINCT a
FROM R
WHERE a >= ALL (SELECT * FROM R)

 

• If R is empty, the query returns empty. The >= ALL test is vacuously true with an empty subquery , but there is no value of a to exploit the test.
• If R holds a NULL value, the query returns empty, because the test a >= ALL(...) returns unknown (not false!) for any NULL or maximum non-NULL integer value of a if the subquery includes a NULL value. 

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yes, I think B) will be ans

https://gateoverflow.in/118391/gate2017-2-46

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@srestha ma'am if they say for non null value then B will be the right answer .But here null is allowed.