出自:Oracle认证
The EMPLOYEES table contains these columns: EMPLOYEE_ID NUMBER(4) ENAME VARCHAR2 (25) JOB_ID VARCHAR2(10) Which SQL statement will return the ENAME, length of the ENAME, and the numeric position of the letter "a" in the ENAME column, for those employees whose ENAME ends with a the letter "n"?（）
A:SELECT ENAME, LENGTH(ENAME), INSTR(ENAME, 'a') FROM EMPLOYEES WHERE SUBSTR (ENAME, -1,1) = 'n';
B:SELECT ENAME, LENGTH(ENAME), INSTR(ENAME, ,-1,1) FROM EMPLOYEES WHERE SUBSTR (ENAME, -1,1) = 'n';
C:SELECT ENAME, LENGTH(ENAME), SUBSTR(ENAME, -1,1) FROM EMPLOYEES WHERE INSTR (ENAME, 1,1) = 'n';
D:SELECT ENAME, LENGTH(ENAME), SUBSTR(ENAME, -1,1) FROM EMPLOYEES WHERE INSTR (ENAME, -1,1) = 'n';
Examine the structure of the STUDENTS table: STUDENT_ID NUMBER NOT NULL, Primary Key STUDENT_NAME VARCHAR2(30) COURSE_ID VARCHAR2(10) NOT NULL MARKS NUMBER START_DATE DATE FINISH_DATE DATE You need to create a report of the 10 students who achieved the highest ranking in the course INT SQL and who completed the course in the year 1999. Which SQL statement accomplishes this task? （）
A:SELECT student_ id, marks, ROWNUM "Rank" FROM students WHERE ROWNUM <= 10 AND finish_date BETWEEN '01-JAN-99' AND '31-DEC-99 AND course_id = 'INT_SQL' ORDER BY mark DESC;
B:SELECT student_id, marks, ROWID "Rank" FROM students WHERE ROWID <= 10 AND finish_date BETWEEN '01-JAN-99' AND '31-DEC-99' AND course_id = 'INT_SQL' ORDER BY mark;
C:SELECT student_id, marks, ROWNUM "Rank" FROM (SELECT student_id, marks FROM students WHERE ROWNUM <= 10 AND finish_date BETWEEN '01-JAN-99' AND '31-DEC- 99' AND course_id = 'INT_SQL' ORDER BY mark DESC;
D:SELECT student_id, marks, ROWNUM "Rank" FROM (SELECT student_id, marks FROM students WHERE (finish_date BETWEEN '01-JAN-99 AND '31-DEC-99' AND course_id = 'INT_SQL' ORDER BY marks DESC) WHERE ROWNUM <= 10;
E:SELECT student id, marks, ROWNUM "Rank" FROM (SELECT student_id, marks FROM students ORDER BY marks) WHERE ROWNUM <= 10 AND finish date BETWEEN '01-JAN-99' AND '31-DEC-99' AND course _ id 'INT_SQL';
A programmer iterates over the TreeSet and prints the name of each Drink object. What is the result？（）
Which two, independently, will allow Sub to compile?（）
View the Exhibit to see the structure of the EMPLOYEES and DEPARTMENTS tables. Your organization plans to dissolve the department with department ID 30. You execute the following command to delete rows from the DEPARTMENTS table： SQL>delete from DEPARTMENTS where DEPT_ID = 30； The command fails and displays the following error： ERROR at line 1： ORA-02292： integrity constraint （HR.SYS_C005374） violated - child record found Which two actions would you take to overcome this error？（）
Which two statements， inserted independently at both lines 35 and 41， tend to allow both threads totemporarily pause and allow the other thread to execute？（）