单项选择题
A.WHERE B.GROUP BY C.SELECT D.FROM
A．DELETE FROM职工WHERE工资=NULL B ．DELETE FROM职I WHERE工资IS NULL C．DELETE FROM职工WHERE工资=!NULL D．DELETE FROM职工WHERE工资IS NOT NULL
A ．REPLACE AGE WITH AGE+5 B ．UPDATE STUDENT AGE WITH AGE+5 C ．UPDATE SET AGE WITH AGE+5 D ．UPDATE STUDENT SET AGE=AGE+5