Oracle
1Z0-882 · Question #22
1Z0-882 Question #22: Real Exam Question with Answer & Explanation
The correct answer is C. The minimal number of rows possible are read.. See the full explanation below for the reasoning.
Question
Inspect the query: Mysql>SELECT dept_no, emp_no FROM employees JOIN dept _manager USING(emp_no) WHERE dept_no'd004'; 4 rows in set (0.00 sec) Mysql>EXPLAIN SELECT dept_no, emp_no FROM employees JOIN dept_manager USING (emp_no) WHERE dept_no='d004'; 2 rows in set (0.00 sec) Which two statements are true about the EXPLAIN output?
Exhibit
Options
- AAll data for the result is read from the indexex.
- BThe PRIMARY KEY is used for filtering in both tables.
- CThe minimal number of rows possible are read.
- DThe dept_manager table has 4 times as many rows than the employees table.
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