多项选择题
A. SELECT TO_CHAR(2000, '$#,###.##') FROM dual;
B. SELECT TO_CHAR(2000, '$0,000.00') FROM dual;
C. SELECT TO_CHAR(2000, '$9,999.00') FROM dual;
D. SELECT TO_CHAR(2000, '$9,999.99') FROM dual;
E. SELECT TO_CHAR(2000, '$2,000.00') FROM dual;
F. SELECT TO_CHAR(2000, '$N,NNN.NN') FROM dual;
单项选择题 Which are iSQL*Plus commands? （）
多项选择题 Examine the description of the MARKS table: STD_ID NUMBER(4) STUDENT_NAME VARCHAR2(30) SUBJ1 NUMBER(3) SUBJ2 NUMBER(3) SUBJ3 NUMBER(3) SUBJ1, SUBJ2, and SUBJ3 indicate the marks (grades) obtained by a student in the three subjects. Which two statements are valid? （）
单项选择题 Examine the description of the EMPLOYEES table: Which statement produces the number of different departments that have employees with last name Smith?（）