Q. A _____ indicates an absent value that may exist but be unknown or that may not exist at all.

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Q. If the attribute phone number is included in the relation all the values need not be entered into the phone number column . This type of entry is given as

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Q. The predicate in a where clause can involve Boolean operations such as and.The result of true and unknown is_______ false and unknown is _____ while unknown and unknown is _____

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Q. In a employee table to include the attributes whose value always have some value which of the following constraint must be used ?

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Q. Using the ______ clause retains only one copy of such identical tuples.

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Q. You attempt to query the database with this command:

SELECT nvl (100 / quantity, NONE)
FROM inventory;

Why does this statement cause an error when QUANTITY values are null?

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Q. The result of _____unknown is unknown.

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Q. Aggregate functions are functions that take a ___________ as input and return a single value.

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Q. A Boolean data type that can take values true, false, and________

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Q. Which of the following should be used to find all the courses taught in the Fall 2009 semester but not in the Spring 2010 semester .

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Q. The phrase “greater than at least one” is represented in SQL by _____

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Q. Which of the following is used to find all courses taught in both the Fall 2009 semester and in the Spring 2010 semester .

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Q. SQL applies predicates in the _______ clause after groups have been formed, so aggregate functions may be used.

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Q. Aggregate functions can be used in the select list or the_______clause of a select statement or subquery. They cannot be used in a ______ clause.

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Q. The ________ keyword is used to access attributes of preceding tables or subqueries in the from clause.

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Q. Which of the following creates temporary relation for the query on which it is defined ?

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Q. Subqueries cannot:

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Q. Which of the following is not a aggregate function ?

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Q. A Delete command operates on ______ relation.

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Q. Delete from r where P;
The above command

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