单项选择题
Which SQL statement returns a numeric value?（）
A.SELECT ADD_MONTHS(MAX(hire_Date), 6) FROM EMP;
B.SELECT ROUND(hire_date) FROM EMP;
C.SELECT sysdate-hire_date FROM EMP;
D.SELECT TO_NUMBER(hire_date + 7) FROM EMP;
相关考题
-
多项选择题
Which two statements complete a transaction? （）
A.DELETE employees;
B.DESCRIBE employees;
C.ROLLBACK TO SAVEPOINT C;
D.GRANT SELECT ON employees TO SCOTT;
E.ALTER TABLE employees SET UNUSED COLUMN sal;
F.SELECT MAX(sal) FROM employees WHERE department_id = 20; -
多项选择题
Which two statements are true about constraints? （）
A.The UNIQUE constraint does not permit a null value for the column.
B.A UNIQUE index gets created for columns with PRIMARY KEY and UNIQUE constraints.
C.The PRIMARY KEY and FOREIGN KEY constraints create a UNIQUE index.
D.The NOT NULL constraint ensures that null values are not permitted for the column. -
单项选择题
What is true about joining tables through an equijoin?（）
A.You can join a maximum of two tables through an equijoin.
B.You can join a maximum of two columns through an equijoin.
C.You specify an equijoin condition in the SELECT or FROM clauses of a SELECT statement.
D.To join two tables through an equijoin, the columns in the join condition must be primary key and foreign key columns.
E.You can join n tables (all having single column primary keys) in a SQL statement by specifying a minimum of n-1 join conditions.
