单项选择题

A. SELECT employee_id, department_id, department_name, ……

Examine the structure of the EMPLOYEES and DEPARTMENTS tables: EMPLOYEESColumn name Data type Remarks
EMPLOYEE_ID NUMBER NOT NULL, Primary Key
EMP_NAME VARCHAR2 (30)
JOB_ID VARCHAR2 (20)
SALARY NUMBER
MGR_ID NUMBER References EMPLOYEE_ID COLUMN
DEPARTMENT ID NUMBER Foreign key to DEPARTMENT ID column of the DEPARTMENTS table
DEPARTMENTSColumn name Data type Remarks
DEPARTMENT_ID NUMBER NOT NULL, Primary Key DEPARTMENT_NAME VARCHAR2(30)
MGR_ID NUMBER References MGR_ID column of the EMPLOYEES table
Evaluate this SQL statement:
SELECT employee_id, e.department_id, department_name, salary
FROM employees e, departments d
WHERE e. department_id = d.department_id;
Which SQL statement is equivalent to the above SQL statement? （）

A. SELECT employee_id, department_id, department_name, salary FROM employees WHERE department_id IN (SELECT department_id FROM departments);
B. SELECT employee_id, department_id, department_name, salary FROM employees NATURAL JOIN departments;
C. SELECT employee_id, d.department_id, department_name, salary FROM employees e JOIN departments d ON e.department _ id = d. department_id;
D. SELECT employee_id, department_id, department_name, Salary FROM employees JOIN departments USING (e.department_id, d.department_id);

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热门试题

单项选择题Which data dictionary table should you query to view the object privileges granted to the user on specific columns? （）

A. USER_TAB_PRIVS_MADE
B. USER_TAB_PRIVS
C. USER_COL_PRIVS_MADE
D. USER_COL_PRIVS

单项选择题CREATE TABLE dept (deptno NUMBER(2), dname VARCNAR2(14), 1oc VARCNAR2 (13)); ROLLBACK; DESCRIBE DEPT What is true about the set? （）

A. The DESCRIBE DEPT statement displays the structure of the DEPT table.
B. The ROLLBACK statement frees the storage space occupies by the DEPT table.
C. The DESCRIBE DEPT statement returns an error ORA-04043: object DEPT does not exist.
D. The DESCRIBE DEPT statement displays the structure of the DEPT table only if there is a COMMIT statement introduced before the ROLLBACK statement.

单项选择题Which SQL statement defines the FOREIGN KEY constraint on the DEPTNO column of the EMP table? （）

A. CREATE TABLE EMP (empno NUMBER(4), ename VARCNAR2(35), deptno NUMBER(7,2) NOT NULL CONSTRAINT emp_deptno_fk FOREIGN KEY deptno REFERENCES dept deptno);
B. CREATE TABLE EMP (empno NUMBER(4), ename VARCNAR2(35), deptno NUMBER(7,2) CONSTRAINT emp_deptno_fk REFERENCES dept (deptno));
C. CREATE TABLE EMP (empno NUMBER(4) ename VARCHAR2(35), deptno NUMBER(7,2) NOT NULL, CONSTRAINT emp_deptno_fk REFERENCES dept (deptno) FOREIGN KEY (deptno));
D. CREATE TABLE EMP (empno NUMBER(4), ename VARCNAR2(35), deptno NUMBER(7,2) FOREIGN KEY CONSTRAINT emp deptno fk REFERENCES dept (deptno));

多项选择题Which three are DATETIME data types that can be used when specifying column definitions? （）

A. TIMESTAMP
B. INTERVAL MONTH TO DAY
C. INTERVAL DAY TO SECOND
D. INTERVAL YEAR TO MONTH
E. TIMESTAMP WITH DATABASE TIMEZONE

单项选择题Evaluate the SQL statement: 1 SELECT a.emp_name, a.sal, a.dept_id, b.maxsal 2 FROM employees a, 3 (SELECT dept_id, MAX(sal) maxsal 4. FROM employees 5 GROUP BY dept_id) b 6 WHERE a.dept_id = b.dept_id 7 AND a. asl < b. maxsal; What is the result of the statement? （）

A. The statement produces an error at line 1.
B. The statement produces an error at line 3.
C. The statement produces an error at line 6.
D. The statement returns the employee name, salary, department ID, and maximum salary earned in the department of the employee for all departments that pay less salary then the maximum salary paid in the company.
E. The statement returns the employee name, salary, department ID, and maximum salary earned in the department of the employee for all employees who earn less than the maximum salary in their department.