A.Both tables have NULL values.
B.You want all unmatched data from one table.
C.You want all matched data from both tables.
D.You want all unmatched data from both tables.
E.One of the tables has more data than the other.
F.You want all matched and unmatched data from only one table.
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A.ALTER TABLE commercials MODIFY (description CHAR2(1000));
B.ALTER TABLE commercials CHANGE (description CHAR2(1000));
C.ALTER TABLE commercials CHANGE (description VARCHAR2(1000));
D.ALTER TABLE commercials MODIFY (description VARCHAR2(1000));
E.You cannot increase the size of a column if the table has rows.
A.ALTER TABLE students ADD PRIMARY KEY student_id;
B.ALTER TABLE students ADD CONSTRAINT PRIMARY KEY (student_id);
C.ALTER TABLE students ADD CONSTRAINT stud_id_pk PRIMARY KEY student_id;
D.ALTER TABLE students ADD CONSTRAINT stud_id_pk PRIMARY KEY (student_id);
E.ALTER TABLE students MODIFY CONSTRAINT stud_id_pk PRIMARY KEY (student_id);
A.A subquery should retrieve only one row.
B.A subquery can retrieve zero or more rows.
C.A subquery can be used only in SQL query statements.
D.Subqueries CANNOT be nested by more than two levels.
E.A subquery CANNOT be used in an SQL query statement that uses group functions.
F.When a subquery is used with an inequality comparison operator in the outer SQL statement, the column list in the SELECT clause of the subquery should contain only one column.
Examine the structure of the EMPLOYEES and NEW_EMPLOYEES tables:
EMPLOYEES
EMPLOYEE_ID NUMBER Primary Key
FIRST_NAME VARCHAR2(25)
LAST_NAME VARCHAR2(25)
HIRE_DATE DATE
NEW_EMPLOYEES
EMPLOYEE_ID NUMBER Primary Key
NAME VARCHAR2(60)
Which UPDATE statement is valid?（）
A.UPDATEnew_employeesSETname=（SELECTlast_nameFirst_nameFROMemployeesWHEREemployee_id=180）WHEREemployee_id=180；
B.UPDATEnew_employeesSETname=（SELECTlast_nameFirst_nameFROMemployees）WHEREemployee_id=180；
C.UPDATEnew_employeesSETname=（SELECTlast_nameFirst_nameFROMemployeesWHEREemployee_id=180） WHEREemployee_id=（SELECTemployee_idFROMnew_employees）；
D.UPDATEnew_employeesSETname=（SELECTlast_nameFirst_nameFROMemployeesWHEREemployee_id=（SELECTemployee_idFROMnew_employees） WHEREemployee_id=180；
A.USER_CONSTRAINTS
B.USER_OBJECTS
C.ALL_CONSTRAINTS
D.USER_CONS_COLUMNS
E.USER_COLUMNS
A.cannot be nested
B.manipulate data items
C.act on each row returned
D.return one result per row
E.accept only one argument and return only one value
F.accept arguments which can be a column or an expression
Evaluate this SQL statement:
e.employee_id, (.15* e.salary) + (.5 * e.commission_pct)
+ (s.sales_amount * (.35 * e.bonus)) AS CALC_VALUE
FROM employees e, sales s
WHERE e.employee_id = s.emp_id;
What will happen if you remove all the parentheses from the calculation?（）
A.The value displayed in the CALC_VALUE column will be lower.
B.The value displayed in the CALC_VALUE column will be higher.
C.There will be no difference in the value displayed in the CALC_VALUE column.
D.An error will be reported.
Examine the structure of the EMPLOYEES table:
Column name Data type Remarks
EMPLOYEE_ID NUMBER NOT NULL, Primary Key
EMP_NAME VARCHAR2(30)
JOB_ID VARCHAR2(20) NOT NULL
SAL NUMBER
MGR_ID NUMBER References EMPLOYEE_ID column
DEPARTMENT_ID NUMBER Foreign key to DEPARTMENT_ID column
of the DEPARTMENTS table
You need to create a view called EMP_VU that allows the users to insert rows through the view. Which SQL statement, when used to create the EMP_VU view, allows the users to insert rows?（）
A.CREATE VIEW emp_vu AS SELECT employee_id, emp_name, department_id FROM employees WHERE mgr_id IN (102, 120);
B.CREATE VIEW emp_vu AS SELECT employee_id, emp_name, job_id, department_id FROM employees WHERE mgr_id IN (102, 120);
C.CREATE VIEW emp_vu AS SELECT department_id, SUM(sal) TOTALSAL FROM employees WHERE mgr_id IN (102, 120) GROUP BY department_id;
D.CREATE VIEW emp_vu AS SELECT employee_id, emp_name, job_id, DISTINCT department_id FROM employees;
A.A WHERE clause can be used to restrict both rows and groups.
B.A WHERE clause can be used to restrict rows only.
C.A HAVING clause can be used to restrict both rows and groups.
D.A HAVING clause can be used to restrict groups only.
E.A WHERE clause CANNOT be used in a query if the query uses a HAVING clause.
F.A HAVING clause CANNOT be used in subqueries.
A.The tables being joined have NOT NULL columns.
B.The tables being joined have only matched data.
C.The columns being joined have NULL values.
D.The tables being joined have only unmatched data.
E.The tables being joined have both matched and unmatched data.
F.Only when the tables have a primary key-foreign key relationship.
最新试题
Which is a valid CREATE TABLE statement? （）
Which four are types of functions available in SQL? （）
Which three are true? （）
Evaluate the SQL statement: TRUNCATE TABLE DEPT; Which three are true about the SQL statement? （）
Which three statements about subqueries are true? （）
A SELECT statement can be used to perform these three functions:1. Choose rows from a table.2. Choose columns from a table3. Bring together data that is stored in different tables by creating a link between them. Which set of keywords describes these capabilities? （）
Evaluate this SQL statement:SELECT e.emp_name, d.dept_nameFROM employees eJOIN departments dUSING (department_id)WHERE d.department_id NOT IN (10,40)ORSER BY dept_name;The statement fails when executed. Which change fixes the error? （）
Which two statements are true about constraints? （）
Which two statements about subqueries are true? （）
You need to perform these tasks:1. Create and assign a MANAGER role to Blake and Clark2. Grant CREATE TABLE and CREATE VIEW privileges to Blake and ClarkWhich set of SQL statements achieves the desired results? （）