What is true of using group functions ...

单项选择题What is true of using group functions on columns that contain NULL values?（）

A. Group functions on columns ignore NULL values.
B. Group functions on columns returning dates include NULL values.
C. Group functions on columns returning numbers include NULL values.
D. Group functions on columns cannot be accurately used on columns that contain NULL values.
E. Group functions on columns include NULL values in calculations if you use the keyword INC_NULLS.

点击查看答案

您可能感兴趣的试卷

你可能感兴趣的试题

1.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? （）

A. SER_NO
B. ORDER_ID
C. STATUS
D. PROD_ID
E. ORD_TOTAL
F. composite index on ORDER_ID and ORDER_DATE

点击查看答案

2.单项选择题Which object privileges can be granted on a view?（）

A. none
B. DELETE, INSERT,SELECT
C. ALTER, DELETE, INSERT, SELECT
D. DELETE, INSERT, SELECT, UPDATE

点击查看答案

3.单项选择题Which SQL statement generates the alias Annual Salary for the calculated column SALARY*12?（）

A. SELECT ename, salary*12 ‘Annual Salary’   FROM employees;
B. SELECT ename, salary*12 “Annual Salary”   FROM employees;
C. SELECT ename, salary*12 AS Annual Salary   FROM employees;
D. SELECT ename, salary*12 AS INITCAP(“ANNUAL SALARY”)   FROM employees

点击查看答案

4.单项选择题What is true about sequences?（）

A. Once created, a sequence belongs to a specific schema.
B. Once created, a sequence is linked to a specific table.
C. Once created, a sequence is automatically available to all users.
D. Only the DBA can control which sequence is used by a certain table.
E. Once created, a sequence is automatically used in all INSERT and UPDATE statements.

点击查看答案

5.单项选择题In which scenario would index be most useful?（）

A. The indexed column is declared as NOT NULL.
B. The indexed columns are used in the FROM clause.
C. The indexed columns are part of an expression.
D. The indexed column contains a wide range of values.

点击查看答案

6.单项选择题 The EMPLOYEES table contains these columns:
EMPLOYEE_ID NUMBER(4)
LAST_NAME VARCHAR2 (25)
JOB_ID VARCHAR2(10)
You want to search for strings that contain 'SA_' in the JOB_ID column. Which SQL statement do you use?（）

A. SELECT employee_id, last_name, job_id FROM employees WHERE job_id LIKE '%SA\_%'ESCAPE'\';
B. SELECT employee_id, last_name, job_id FROM employees WHERE job_id LIKE '%SA_';
C. SELECT employee_id, last_name, job_id FROM employees WHERE job_id LIKE '%SA_'ESCAPE'\';
D. SELECT employee_id, last_name, job_id FROM employees WHERE job_id '%SA_';

点击查看答案

7.单项选择题 Examine the structure of the EMPLOYEES table:

You issue these statements:

At the end of this transaction, what is true?（）

A. You have no rows in the table.
B. You have an employee with the name of James.
C. You cannot roll back to the same savepoint more than once.
D. Your last update fails to update any rows because employee ID 180 was already eleted.

点击查看答案

8.单项选择题 The user Sue issues this SQL statement:
GRANT SELECT ON sue. EMP TO alice WITH GRANT OPTION;
The user Alice issues this SQL statement:
GRANT SELECT ON sue. EMP TO reena WITH GRANT OPTION;
The user Reena issues this SQL statement:
GRANT SELECT ON sue. EMP TO timber;
The user Sue issues this SQL statement:
REVOKE select on sue. EMP FROM alice;
For which users does the revoke command revoke SELECT privileges on the SUE.EMP table?（）

A. Alice only
B. Alice and Reena
C. Alice, Reena, and Timber
D. Sue, Alice, Reena, and Timber

点击查看答案

9.多项选择题 Examine the structure of the EMPLOYEES table:
EMPLOYEE_ID NUMBER Primary Key
FIRST_NAME VARCHAR2(25)
LAST_NAME VARCHAR2(25)
Which three statements insert a row into the table? （）

A. INSERT INTO employees VALUES (NULL, 'John', 'smith');
B. INSERT INTO employees (first_name, last_name) VALUES ('John', 'smith');
C. INSERT INTO employees VALUES ('1000, 'John', 'smith');
D. INSERT INTO employees (first_name, last_name, employee_id) VALUES (1000, 'John', 'smith');
E. INSERT INTO employees (employee_id) VALUES (1000);
F. INSERT INTO employees ( employee_id, first_name, last_name, ) VALUES (1000, 'John','');

点击查看答案

10.单项选择题 Mary has a view called EMP_DEPT_LOC_VU that was created based on the EMPLOYEES, DEPARTMENTS, and LOCATIONS tables. She granted SELECT privilege to Scott on this view.
Which option enables Scott to eliminate the need to qualify the view with the name MARY .EMP_DEP_LOC_VU each time the view is referenced?（）

A. Scott can create a synonym for the EMP_DEPT_LOC_VU bus using the command:   CREATE PRIVATE SYNONYM EDL_VU   FOR mary.EMP DEPT_LOC_VU;   then he can prefix the columns with this synonymn.
B. Scott can create a synonym for the EMP_DEPT_LOC_VU by using the command:   CREATE SYNONYM EDL_VU   FOR mary.EMP_DEPT_LOC_VU;   then he can prefix the columns with this synonym.
C. Scott can create a synonym for the EMP_DEPT_LOC_VU by using the command:   CREATE LOCAL SYNONYM EDL_VU   FOR mary.EMP DEPT_LOC_VU;   then he can prefix the columns with this synonym.
D. Scott can create a synonym for the EMP_DEPT_LOC_VU by using the command:   CREATE SYNONYM EDL_VU   ON mary(EMP_DEPT_LOC_VU);   then he can prefix the columns with this synonym.
E. Scott cannot create a synonym because synonyms can be created only for tables.
F. Scott cannot create any synonym for Mary’s view. Mary should create a private ynonym for the view and grant SELECT privilege on that synonym to Scott.

点击查看答案