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Consider the query:Mysql＞ SET @run = 15;Mysql＞ EXPLAIN SELECT objective, stage, COUNT （sta

Consider the query:Mysql＞ SET @run = 15;Mysql＞ EXPLAIN SELECT objective, stage, COUNT (stage)FROM iteminformationWHERE run=@run AND objective=’7.1’GROUP BY objective,stageORDER BY stage;The iteminformation table has the following indexes;Mysql＞ SHOW INDEXES FROM iteminformation:This query is run several times in an application with different values in the WHERE clause in a growing data set.What is the primary improvement that can be made for this scenario？（）

Consider the query:Mysql＞ SET @run = 15;Mysql＞ EXP

Consider the query:Mysql＞ SET @run = 15;Mysql＞ EXP

A.Do not pass a user variable in the WHERE clause because it limits the ability of the optimizer to use indexes

B.Add an index on the objective column so that is can be used in both the WHERE and GROUP BY operations

C.Drop the run_2 index because it has caused a conflict in the choice of key for this query

D.Execute the run_2 index because it has caused a conflict in the choice of key for this query

E.Add a composite index on (run,objective,stage) to allow the query to fully utilize an index

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第5题

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第6题

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第8题

Click the Exhibit button and examine the data in the EMPLOYEES and DEPARTMENTS tables.You

want to retrieve all employees‘ last names, along with their managers‘ last names and their department names. Which query would you use？（）

Click the Exhibit button and examine the data in t

A.SELECT last_name, manager_id, department_name FROM employees e FULL OUTER JOIN departments d ON (e.department_id = d.department_id);

B.SELECT e.last_name, m.last_name, department_name FROM employees e LEFT OUTER JOIN employees m on (e.manager_id = m.employee_id) LEFT OUTER JOIN departments d ON (e.department_id = d.department_id);

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F.SELECT last_name, manager_id, department_name FROM employees e JOIN departments d ON (e.department_id = d.department_id) ;

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第9题

ExhibitExamine the data in the EMPLOYEES and DEPARTMENTS tables.You want to retrieve all e

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A. SELECT last_name, manager_id, department_name FROM employees e FULL OUTER JOIN department d ON (e.department_id = d.department_id);

B. SELECT e.last_name, m.last_name, department_name FROM employees e LEFT OUTER JOIN employees m on (e.managaer_id = m.employee_id) LEFT OUTER JOIN department d ON (e.department_id = d.department_id);

C. SELECT e.last_name, m.last_name, department_name FROM employees e RIGT OUTER JOIN employees m on (e.manager_id = m.employee_id) FULL OUTER JOIN department d ON (e.department_id = d.department_id);

D. SELECT e.last_name, m.last_name, department_name FROM employees e LEFT OUTER JOIN employees m on (e.manager_id = m.employee_id) RIGT OUTER JOIN department d ON (e.department_id = d.department_id);

E. SELECT e.last_name, m.last_name, department_name FROM employees e RIGHT OUTER JOIN employees m on (e.manager_id = m.employee_id) RIGHT OUTER JOIN departments d ON (e.department_id = d.department_id)

F. SELECT last_name, manager_id, department_name FROM employees e JOIN department d ON (e.department_id = d.department_id);

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第10题

The EMPLOYEE table contains the following information: EMPNO NAME WORKDEPT101 SAM A11 102

JOHN C12 103 JANE -104 PAT Remote105 ANNE -106 BOB A11The MANAGER table contains the following information: MGRID NAME DEPTNO EMPCOUNT1 WU B01 - 2 JONES A11 - 3 CHEN - - 4 SMITH - -5 THOMAS C12 -After this statement is executed: UPDATE manager m SET empcount = (SELECT COUNT(workdept) FROM employee e WHERE workdept=m.deptno)What is the result of the following query？（）SELECT mgrid, empcount FROM MANAGER WHERE empcount IS NOT NULL ORDER BY mgrid

A. MGRID EMPCOUNT ----- -------- 1 0 2 2 5 1

B. MGRID EMPCOUNT ----- -------- 1 0 2 2 3 0 4 0 5 1

C. MGRID EMPCOUNT ----- -------- 1 3 2 3 3 3 4 3 5 3

D. MGRID EMPCOUNT ----- -------- 1 0 2 2 3 2 4 2 5 1

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