单项选择题
A.SELECT*FROMemp_dept_vu；
B.SELECTdepartment_id，SUM（salary）FROMemp_dept_vuGROUPBYdepartment_id；
C.SELECTdepartment_id，job_id，AVG（salary）FROMemp_dept_vuGROUPBYdepartment_id，job_id；
D.SELECTjob_id，SUM（salary）FROMemp_dept_vuWHEREdepartment_idIN（10，20）GROUPBYjob_idHAVINGSUM（salary）>；20000；
E.Noneofthestatementsproduceanerror；allarevalid
多项选择题 Examine the SQL statement that creates ORDERS table: CREATE TABLE orders (SER_NO NUMBER UNIQUE, ORDER_ID NUMBER, ORDER_DATE DATE NOT NULL, STATUS VARCHAR2(10) CHECK (status IN (CREDIT, CASH)), PROD_ID NUMBER REFERENCES PRODUCTS(PRODUCT_ID), ORD_TOTAL NUMBER, PRIMARY KEY (order_id, order_date)); For which columns would an index be automatically created when you execute the above SQL statement? （）
单项选择题 Evaluate this SQL statement: SELECT ename, sal, 12*sal+100 FROM emp; The SAL column stores the monthly salary of the employee. Which change must be made to the above syntax to calculate the annual compensation as "monthly salary plus a monthly bonus of $100, multiplied by 12"?（）
单项选择题 Evaluate the set of SQL statements: CREATE TABLE dept (deptno NUMBER(2), dname VARCHAR2(14), loc VARCHAR2(13)); ROLLBACK; DESCRIBE DEPT What is true about the set?（）