READ Free Dumps For Oracle- 1z0-001
| Question ID 8112 | In which order does the Oracle Server evaluate clauses?
|
| Option A | HAVING, WHERE, GROUP BY
|
| Option B | WHERE, GROUP BY, HAVING
|
| Option C | GROUP BY, HAVING, WHERE
|
| Option D | WHERE, HAVING, GROUP BY
|
| Correct Answer | B |
Explanation Explanation/Reference: Explanation: Answer B is correct because the Oracle server first evaluate WHERE clause to reduce number of rows that need to be processed, than GROUP BY clause and after that HAVING clause. Incorrect Answers: A: Order of clauses evaluation is incorrect because WHERE clause will be processed first. C: Order of clauses evaluation is incorrect because WHERE clause will be processed first. D: Order of clauses evaluation is incorrect because HAVING clause cannot be processed before GROUP BY clause. Oracle 8, DBA Certification Exam Guide, Jason S. Couchman, p. 60-64 Chapter 2: Advanced Data Selection in Oracle
| Question ID 8113 | In which situation should you use outer join query?
|
| Option A | The employee table has two columns that correspond.
|
| Option B | The employee and region tables have corresponding columns.
|
| Option C | The employees and region tables have no correspondence.
|
| Option D | The employee table column correspond to the region table column contains null values for rows that need to be displayed.
|
| Correct Answer | D |
Explanation Explanation/Reference: Explanation: Answer D is correct because to show all data including null values for rows that need to be displayed you need to use OUTER join between two tables. Notice the special (+) character string called the outer join operator that forms the join. Incorrect Answers: A: You don't need to use outer join if the employee table has two columns that correspond. B: You don't need to use outer join if the employee table and region table have columns that correspond. C: You don't need to use outer join if the employee table and region table have no columns that correspond. Oracle 8, DBA Certification Exam Guide, Jason S. Couchman, p. 53-55 Chapter 2: Advanced Data Selection in Oracle