查询选修了课程号为“C2”的学生中成绩最高的学生的学号,正确的SELECT语句是()。 A: SELECTS B: FROMSC WHEREC C: ='C2'ANDGRADE>=ALL D: (SELECTGRADE FROMSC WHEREC E: ='C2') F: SELECTS G: FROMSC WHEREC H: ='C2'ANDGRADEIN I: (SELECTMAX(GRADE) FROMSC WHEREC J: ='C2') K: SELECTS L: FROMSC WHEREC M: ='C2'ANDGRADE= N: (SELECTMAX(GRADE) FROMSC WHEREC O: ='C2') P: SELECTS Q: FROMSC WHEREC R: ='C2'ANDGRADE>=ANY S: (SELECTGRADE FROMSC WHEREC T: ='C2')
查询选修了课程号为“C2”的学生中成绩最高的学生的学号,正确的SELECT语句是()。 A: SELECTS B: FROMSC WHEREC C: ='C2'ANDGRADE>=ALL D: (SELECTGRADE FROMSC WHEREC E: ='C2') F: SELECTS G: FROMSC WHEREC H: ='C2'ANDGRADEIN I: (SELECTMAX(GRADE) FROMSC WHEREC J: ='C2') K: SELECTS L: FROMSC WHEREC M: ='C2'ANDGRADE= N: (SELECTMAX(GRADE) FROMSC WHEREC O: ='C2') P: SELECTS Q: FROMSC WHEREC R: ='C2'ANDGRADE>=ANY S: (SELECTGRADE FROMSC WHEREC T: ='C2')
基于教材上的选课表SC,使用嵌套查询查找所有超过所选课程平均分的学生选课记录,正确的SQL语句是________。 A: SELECTSno, Cno, Grade FROMSC SC1WHERE Grade>;(SELECT AVG(Grade) FROMSC SC2); B: SELECTSno, Cno, Grade FROMSC SC1WHERE Grade>;(SELECT AVG(Grade) FROMSC SC2 WHERE SC2.Cno=SC1.Cno); C: SELECTSno, Cno, Grade FROMSC SC1WHERE Grade>;(SELECT AVG(Grade) FROMSC SC2 GROUP BY SC2.Cno); D: SELECTSno, Cno, Grade FROMSC SC1WHERE AVG(Grade)>;(SELECT Grade FROMSC SC2 WHERE SC2.Cno=SC1.Cno);
基于教材上的选课表SC,使用嵌套查询查找所有超过所选课程平均分的学生选课记录,正确的SQL语句是________。 A: SELECTSno, Cno, Grade FROMSC SC1WHERE Grade>;(SELECT AVG(Grade) FROMSC SC2); B: SELECTSno, Cno, Grade FROMSC SC1WHERE Grade>;(SELECT AVG(Grade) FROMSC SC2 WHERE SC2.Cno=SC1.Cno); C: SELECTSno, Cno, Grade FROMSC SC1WHERE Grade>;(SELECT AVG(Grade) FROMSC SC2 GROUP BY SC2.Cno); D: SELECTSno, Cno, Grade FROMSC SC1WHERE AVG(Grade)>;(SELECT Grade FROMSC SC2 WHERE SC2.Cno=SC1.Cno);
“SELECTCOUNT(DISTINCTSno)FROMSC”语句用于统计学生的总人数。()
“SELECTCOUNT(DISTINCTSno)FROMSC”语句用于统计学生的总人数。()
查询选了课的学生人数:SELECTCOUNT(SNO)FROMSC;
查询选了课的学生人数:SELECTCOUNT(SNO)FROMSC;
根据SQL标准,把表SC1中的记录复制到另一个表SC2中,其中SC1表和SC2表的字段定义完全一样。下面哪条语句适用?() A: copy*fromSC1toSC2 B: copy*fromSC2toSC1 C: insertintoSC2select*fromSC1 D: insertintoSC1select*fromSC2
根据SQL标准,把表SC1中的记录复制到另一个表SC2中,其中SC1表和SC2表的字段定义完全一样。下面哪条语句适用?() A: copy*fromSC1toSC2 B: copy*fromSC2toSC1 C: insertintoSC2select*fromSC1 D: insertintoSC1select*fromSC2
有表student(sno,sname,ssex,sbirth,sdept);表course(cno,cname);表sc(sno,cno,degree),查询选修了课程的学号,使用的FROM子句正确的是:() A: FROMsc B: FROMstudent C: FROMcourse D: FROMsno
有表student(sno,sname,ssex,sbirth,sdept);表course(cno,cname);表sc(sno,cno,degree),查询选修了课程的学号,使用的FROM子句正确的是:() A: FROMsc B: FROMstudent C: FROMcourse D: FROMsno
for i in range(b.max_row): for j in range(b.max_column): print(b.cell(row=i,column=j).value)上面语句运行的结果是:__________。 A: 1 1 1 1 1 1 1 1 1 1 B: 1111111111 C: 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 D: 出现异常
for i in range(b.max_row): for j in range(b.max_column): print(b.cell(row=i,column=j).value)上面语句运行的结果是:__________。 A: 1 1 1 1 1 1 1 1 1 1 B: 1111111111 C: 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 D: 出现异常
【单选题】CDMA通信的基站,假定基站A的码片序列是+1 +1 +1 -1 -1 +1 -1 -1,基站发射bit为101时,实际发射的信号是 A. +1 +1 +1 -1 -1 +1 -1 -1 +1 +1 +1 -1 -1 +1 -1 -1 –1 –1 –1 +1 +1 –1 +1 +1 B. +1 +1 +1 -1 -1 +1 -1 -1 –1 –1 –1 +1 +1 –1 +1 +1 +1 +1 +1 -1 -1 +1 -1 -1 C. +1 +1 +1 -1 -1 +1 -1 -1 +1 +1 +1 -1 -1 +1 -1 -1 +1 +1 +1 -1 -1 +1 -1 -1 D. –1 –1 –1 +1 +1 –1 +1 +1 –1 –1 –1 +1 +1 –1 +1 +1 –1 –1 –1 +1 +1 –1 +1 +1
【单选题】CDMA通信的基站,假定基站A的码片序列是+1 +1 +1 -1 -1 +1 -1 -1,基站发射bit为101时,实际发射的信号是 A. +1 +1 +1 -1 -1 +1 -1 -1 +1 +1 +1 -1 -1 +1 -1 -1 –1 –1 –1 +1 +1 –1 +1 +1 B. +1 +1 +1 -1 -1 +1 -1 -1 –1 –1 –1 +1 +1 –1 +1 +1 +1 +1 +1 -1 -1 +1 -1 -1 C. +1 +1 +1 -1 -1 +1 -1 -1 +1 +1 +1 -1 -1 +1 -1 -1 +1 +1 +1 -1 -1 +1 -1 -1 D. –1 –1 –1 +1 +1 –1 +1 +1 –1 –1 –1 +1 +1 –1 +1 +1 –1 –1 –1 +1 +1 –1 +1 +1
for i in range(1,11): for j in range(1,11): b.cell(row=i,column=j).value=1 #b是一个工作表对象for i in range(1,11): for j in range(1,11): print(b.cell(row=i,column=j).value,end=" ") print()上面程序代码运行的结果是()。 A: 1 B: 1 1 1 1 1 1 1 1 1 1 C: 1111111111 D: 1 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 1
for i in range(1,11): for j in range(1,11): b.cell(row=i,column=j).value=1 #b是一个工作表对象for i in range(1,11): for j in range(1,11): print(b.cell(row=i,column=j).value,end=" ") print()上面程序代码运行的结果是()。 A: 1 B: 1 1 1 1 1 1 1 1 1 1 C: 1111111111 D: 1 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 1
下列哪个码片序列不能用于CDMA通信 A: ( -1 -1 -1 +1 +1 -1 +1 +1 ) B: ( -1 -1 +1 -1 +1 +1 +1 -1 ) C: ( -1 +1 -1 +1 +1 -1 -1 -1 ) D: ( -1 +1 -1 -1 -1 -1 +1 -1 )
下列哪个码片序列不能用于CDMA通信 A: ( -1 -1 -1 +1 +1 -1 +1 +1 ) B: ( -1 -1 +1 -1 +1 +1 +1 -1 ) C: ( -1 +1 -1 +1 +1 -1 -1 -1 ) D: ( -1 +1 -1 -1 -1 -1 +1 -1 )