Question 4

When using a comparison operator (e.g. = > < >= <= etc.) against a subquery, the subquery must return a single value (one row, one column); otherwise an error will result. What is one method to make this type of comparison and avoid the error?

Question 4 options:

	Convert numeric values to strings
	Include multiple columns in your SELECT clause
	Code the condition with one of the keywords ANY, SOME, or ALL
	Write the subquery using an aggregate calculation

Question 5

WHERE clause comparisons against a subquery can use comparison operators (e.g. + > < >= <= etc.). What is the effect when the ALL keyword is applied to this type of comparison?

Question 5 options:

	The comparison will now be true when multiple rows are returned
	The comparison will now be false if the subquery returns no rows
	The condition must now be true for every value returned from the subquery
	The condition can now be true for any value returned from the subquery

Question 6

WHERE clause comparisons against a subquery can use comparison operators (e.g. + > < >= <= etc.). TheANY and SOME keywords can be applied to this type of comparison to match part of the returned set of values. What is the functional difference between ANY and SOME?

Question 6 options:

	None of the above; they are equivalent
	ANY works only against the equality operator ( + )
	The ANY comparison will typically return more values
	The SOME comparison will typically return more values

Question 7

Which of the following are true about correlated subqueries when used in WHERE clause conditions? Check only those that apply:

Question 7 options:

	When using the same table as the outer query, they require the use of an alias
	They refer to a value provided by a column in the outer query
	They are executed once for each row processed by the outer query
	They typically run more efficiently than non-correlated subqueries
	For testing, they can be executed independently from the outer query without modification

Question 8

Which of the following is true when using the EXISTS comparison against a subquery in the WHERE clause?

Question 8 options:

	Values the subquery can be displayed in the output
	You cannot use a correlation in the subquery
	The subquery must SELECT only a single column
	It resolves as true when the subquery returns any rows

Question 9

A subquery can be placed in the FROM clause of an outer query to act as a kind of "virtual" table (it must be assigned an alias, and all calculated values must be given labels). What is the name given to this type of subquery?

Question 9 options:

	A view table
	A formulated table
	A derived table
	A calculated table

Question 10

Which is true when using a subquery in the SELECT clause of an outer query?

Question 10 options:

	They can return multiple columns, but only a single row
	They can return any number of rows and columns
	They must return only a single value
	They can return multiple rows, but only a single column