Oracle Updated 1z0-071 Exam Questions and Answers by bella-rose

Based on the given PRODUCTS table and the SQL queries provided:

Query 1: Excludes rows where prod_list is 10 or 20 and category_id is 1.

Query 2: Includes rows where prod_list is neither 10 nor 20 and category_id is 1.

Query 3: Excludes rows where prod_list is both 10 and 20 (which is not possible for a single value) and category_id is 1.

The correct answer is A, queries 1 and 3 will produce the same result. Both queries exclude rows where prod_list is 10 or 20 and include only rows from category_id 1. The NOT IN operator excludes the values within the list, and <> ALL operator ensures that prod_list is not equal to any of the values in the list, which effectively excludes the same set of rows.

Query 2, using the <> ANY operator, is incorrect because this operator will return true if prod_list is different from any of the values in the list, which is not the logic represented by the other two queries.

The query's goal is to return a list of countries that have no departments linked to them.

Option B and Option D are the correct answers because they use set operations that will effectively return countries that do not have a corresponding entry in the departments table:

Option B uses the NOT IN subquery to exclude countries that have departments linked to them. It looks for country_id values in the countries table that are not present in the list of country_id values associated with locations that are, in turn, associated with departments. This will correctly return countries that have no departments.

Option D uses the MINUS set operator, which subtracts the results of the second SELECT statement from the results of the first. This statement will return all countries from the countries table minus those that have an associated department_id in the departments table, effectively listing countries with no departments.

Option A and Option C are incorrect because:

Option A will not execute successfully as it tries to join tables using a column (country_id) that doesn't exist in the departments table, which will lead to an error.

Option C's use of INTERSECT is incorrect for this requirement. INTERSECT returns only the rows that exist in both queries. Since we want countries with no departments, using INTERSECT would actually return the opposite of what is required.

References:

Oracle Documentation on NOT IN clause: SQL Language Reference - Subquery

Oracle Documentation on MINUS operator: SQL Language Reference - Set Operators

Therefore, the correct options are B and D, which use subquery exclusion and the MINUS set operator, respectively, to accurately identify and return countries without departments.