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【单项选择题】

列出EMP表中，从事每个工种（JOB）的员工人数（）

A、A.select job from emp;

B、B.select job,count(*) from emp;

C、C.select distinct job,count(*) from emp;

D、D.select job,count(*) from emp group by job;

E、E.select job,sum(empno) from emp group by job;

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更多“列出EMP表中，从事每个工种（JOB）的员工人数（）”相关的问题
第1题
[多选题] 数据库中有一张表名为Emp，包含有如下列：EmpNO（雇员编号，Varchar（20），Pk），Job（职位Varchar（10）），HirDate（雇佣日期，Date），Sal（月薪，Float）。查询出职位不为“办事员”的雇员信息是（）

A、Select *From Emp Where Job>="办事员"  B、Select* From Emp Where Job==’办事员’  C、Select* From Emp Where Job<>’办事员’  D、Select* From Emp Where Job!=’办事员’  

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第2题
[] 有如下三步操作,并且均成功执行,请选择结果（） delete from emp; alter table emp add(addr varchar2(40)); rollback; 有如下三步操作,并且均成功执行,请选择结果（） delete from emp; alter table emp add(addr varchar2(40)); rollback;

A、A. emp表中数据处于回滚段中  B、B. emp表中的数据被永久删除  C、C. emp表中的数据没有变化  D、D. 原来的emp表中的数据被添加到新emp表中  E、E. 以上所述都不正确  

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第3题
[单选题] Examine the data in the EMPLOYEES and EMP_HIST tables: EMPLOYEES NAME DEPT_ID MGR_ID JOB_ID SALARY EMPLOYEE_ID 101 Smith 20 120 SA_REP 4000 102 Martin 10 105 CLERK 2500 103 Chris 20 120 IT_ADMIN 4200 104 John 30 108 HR_CLERK 2500 105 Diana 30 108 IT_ADMIN 5000 106 Smith 40 110 AD_ASST 3000 108 Jennifer 30 110 HR_DIR 6500 110 Bob 40 EX_DIR 8000 120 Ravi 20 110 SA_DIR 6500 EMP HIST EMPLOYEE_ID NAME JOB_ID SALARY 101 Smith SA_CLERK 2000 103 Chris IT_CLERK 2200 104 John HR_CLERK 2000 106 Smith AD_ASST 3000 108 Jennifer HR_MGR 4500 The EMP_HIST table is updated at the end of every year. The employee ID, name, job ID, and salary of each existing employee are modified with the latest data. New employee details are added to the table. Which statement accomplishes this task?（）

A、UPDATE emp_hist SET employee_id, name, job_id, salary = (SELECT employee_id, name, job_id, salary FROM employees) WHERE employee_id IN (SELECT employee_id FROM employees);  B、MERGE INTO emp_hist eh USING employees e ON (eh.employee_id = e.employee_id) WHEN MATCHED THEN UPDATE SET eh.name = e.name, eh.job_id = e.job_id, eh.salary = e.salary WHEN NOT MATCHED THEN INSERT VALUES (e.employee id, e.name, job id, e.salary);  C、MERGE INTO emp_hist eh USING employees e ON (eh.employee_id = e.employee_id) WHEN MATCHED THEN UPDATE emp hist SET eh.name = e.name, eh.job_id = e.job_id, eh.salary = e.salary WHEN NOT MATCHED THEN INSERT INTO emp_hist VALUES (e.employees_id, e.name, e.job_id, e.salary);  D、MERGE INTO emp_hist eh USING employees e WHEN MATCHED THEN UPDATE emp_hist SET eh.name = e.name, eh.job_id = e.job_id, eh.salary = e.salary WHEN NOT MATCHED THEN INSERT INTO emp_hist VALUES (e.employees_id, e.name, e.job_id, e.salary);  

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第4题
[单选题] Examine the structure of the EMP_DEPT_VU view: Column Name Type Remarks EMPLOYEE_ID NUMBER From the EMPLOYEES table EMP_NAME VARCHAR2(30) From the EMPLOYEES table JOB_ID VARCHAR2(20) From the EMPLOYEES table SALARY NUMBER From the EMPLOYEES table DEPARTMENT_ID NUMBER From the DEPARTMENTS table DEPT_NAME VARCHAR2(30) From the DEPARTMENTS table Which SQL statement produces an error?（）

A、SELECT * FROM emp_dept_vu;  B、SELECT department_id, SUM(salary) FROM emp_dept_vu GROUP BY department _ id;  C、SELECT department_id, job_id, AVG(salary) FROM emp_dept_vu GROUP BY department _ id, job_id;  D、SELECT job_id, SUM(salary) FROM emp_dept_vu WHERE department_id IN (10,20) GROUP BY job_id HAVING SUM (salary) > 20000  E、None of the statements produce an error; all are valid.  

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第5题
[单选题] 限制从EMP表中只选出前5条记录的查语句为（）。

A、SELECT TOP 5 * FROM EMP  B、SELECT DISTINCT 5 * FROM EMP  C、SELECT * FROM EMP WHERE ROWNUM<6  D、SELECT * FROM EMP WHERE ROWNUM=5  

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第6题
[单选题] emp表是雇员信息表，以下哪个变量可以存放emp表中的一条记录（）

A、v_record emp%type;  B、v_record emp%recordtype;  C、v_record emp%record_type;  D、v_record emp%rowtype;  E、v_record emp%row_type;  

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第7题
[] Examine the structure of the EMP_DEPT_VU view: Column Name Type Remarks EMPLOYEE_ID NUMBER From the EMPLOYEES table EMP_NAME VARCHAR2(30) From the EMPLOYEES table JOB_ID VARCHAR2(20) From the EMPLOYEES table SALARY NUMBER From the EMPLOYEES table DEPARTMENT_ID NUMBER From the DEPARTMENTS table DEPT_NAME VARCHAR2(30) From the DEPARTMENTS table Which SQL statement produces an error?（） Examine the structure of the EMP_DEPT_VU view: Column Name Type Remarks EMPLOYEE_ID NUMBER From the EMPLOYEES table EMP_NAME VARCHAR2(30) From the EMPLOYEES table JOB_ID VARCHAR2(20) From the EMPLOYEES table SALARY NUMBER From the EMPLOYEES table DEPARTMENT_ID NUMBER From the DEPARTMENTS table DEPT_NAME VARCHAR2(30) From the DEPARTMENTS table Which SQL statement produces an error?（）

A、A. SELECT * FROM emp_dept_vu;  B、B. SELECT department_id, SUM(salary) FROM emp_dept_vu GROUP BY department _ id;  C、C. SELECT department_id, job_id, AVG(salary) FROM emp_dept_vu GROUP BY department _ id, job_id;  D、D. SELECT job_id, SUM(salary) FROM emp_dept_vu WHERE department_id IN (10,20) GROUP BY job_id HAVING SUM (salary) > 20000  E、E. None of the statements produce an error; all are valid.  

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第8题
[多选题] User SCOTT executes the following command on the EMP table but has not issued COMMIT， ROLLBACK，or any data definition language （DDL） command：  SQL> SELECT job FROM emp  2  WHERE job=’CLERK’ FOR UPDATE OF empno;  SCOTT has opened another session to work with the database. Which three operations would wait when issued in SCOTT’s second session？（）

A、LOCK TABLE emp IN SHARE MODE;  B、LOCK TABLE emp IN EXCLUSIVE MODE;  C、DELETE FROM emp WHERE job=’MANAGER’;  D、INSERT INTO emp（empno，ename） VALUES （1289，’Dick’）;  E、SELECT job FROM emp WHERE job=’CLERK’ FOR UPDATE OF empno;  

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第9题
[多选题] 数据库中有一张表名为Emp，包含有如下列：EmpNO（雇员编号，Varchar（20），Pk），Job（职位Varchar（10）），HirDate（雇佣日期，Date），Sal（月薪，Float）。要求查询全部雇员信息应该是哪些数据？（）

A、Select * From Emp  B、Select * From Emp Where EmpNO Like '%%'  C、Select * From Emp Where Name = '%%'  D、Select * From Emp Where Name Like '%%'  

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