A.substitution variables
B.replacement variables
C.prompt variables
D.instead-of variables
E.This feature cannot be implemented through iSQL*Plus.

A.INSTR returns the numeric position of a named character.
B.NVL2 returns the first non-null expression in the expression list.
C.TRUNCATE rounds the column, expression, or value to n decimal places.
D.DECODE translates an expression after comparing it to each search value.
E.TRIM trims the heading or trailing characters (or both) from a character string.
F.NVL compares two expressions and returns null if they are equal, or the first expression if they are not equal.
G.NULLIF compares two expressions and returns null if they are equal, or the first expression if they are not equal.

A.SELECT dept_id, MIN(salary), MAX(salary) FROM employees WHERE MIN(salary) < 5000 AND MAX(salary) > 15000;
B.SELECT dept_id, MIN(salary), MAX(salary) FROM employees WHERE MIN(salary) < 5000 AND MAX(salary) > 15000 GROUP BY dept_id;
C.SELECT dept_id, MIN(salary), MAX(salary) FROM employees HAVING MIN(salary) < 5000 AND MAX(salary) > 15000;
D.SELECT dept_id, MIN(salary), MAX(salary) FROM employees GROUP BY dept_id HAVING MIN(salary) < 5000 AND MAX(salary) > 15000;
E.SELECT dept_id, MIN(salary), MAX(salary) FROM employees GROUP BY dept_id, salary HAVING MIN(salary) < 5000 AND MAX(salary) > 15000;

A.COMMIT
B.MERGE
C.UPDATE
D.DELETE
E.CREATE
F.DROP...

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.

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.

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