1、下列函数中,正确的是( ) A、SUM(*)
B、MAX(*)
C、COUNT(*)
D、AVG(*)
2、检索所有比“王华”年龄大的学生姓名、年龄 和性别。正确的SELECT语句是() A、SELECT SN,AGE,SEX FROM S WHERE AGE>(SELECT AGE FROM S WHERE SN=‘王华’) B、SELECT SN,AGE,SEX FROM S WHERE AGE>(SELECT AGE WHERE SN=‘王华’) C、SELECT SN,AGE,SEX FROM S WHERE SN=‘王华’ D、SEL ECT SN,AGE,SEX FROM S WHERE AGE>王华.AGE
3.在SQL中， 与"NOT IN"等价的操作符是 A、= SOME B、<> SOME , C、<> ALL D、= ALL
4.检索选修课程“C2”的学生中成绩最高的学生的学号。正确的SELECT语句是( ) A、SELECT S# FORM SC WHERE C#=“C2” AND GRADE>=(SELECT GRADE FORM SC WHERE C#=“C2”) B、 SELECT S# FORM SC WHERE C#=“C2” AND GRADE IN (SEL ECT GRADE FORM SC WHERE C#=“C2”) C、SELECT S# FORM SC WHERE C#=“C2” AND GRADE NOT IN (SELECT GRADE FORM SC WHERE C#=“C2”) D、SELECT S# FORM SC WHERE C#="C2”AND GRADE>=ALL (SELECT GRADE FORM SC WHERE C#=“C2”)
5.要建立一个约束，保证用户表（user）中年龄（age）必须在16岁以上，下面语句中正确的是 正确答案：D
