有志者事竟成。中译英
A、Where there is a will there is a way.
B、Sucess comes from strong will.
A、Where there is a will there is a way.
B、Sucess comes from strong will.
A.where to choose
B.which to choose
C.to choose what
D.to choose which
A."
B.can
C.may
D.must
E.ought to
A.that
B.which
C.where
D.what
此题为判断题(对,错)。
A.what
B.that
C.where
D.it
已知4个关系: S(sno,sname,sex,age,dept,special) C(cno,cname,credit,dept,precno,tno) T(tno,tname,sex,tspecial) SC(sno,cno,grade) 检索“通信”和“计算机”专业情况的语句是()。
A.SELECT* FROM S WHERE special='通信' OR special='计算机'
B.SELECT* PROM S WHERE special='通信' AND special='计算机'
C.SELECT* FROMT WHERE special='通信' OR special='计算机'
D.SELECT* FROM T WHERE special='通信' AND special='计算机'
A.SELECT 学号,课程号 FROM sc WHERE 成绩=""
B.SELECT 学号,课程号 FROM sc WHERE 成绩=NULL
C.SELECT 学号,课程号 FROM sc WHERE 成绩 IS NULL
D.SELEC T学号,课程号 FROM sc WHERE 成绩
设学生选课关系模式为SC(Sno,Cno,Grade),其中,Sno为学号,Cno为课程号, Grade为成绩,SQL查询语句如下:
SELECT Sno
FROMSC SCX
WHERE NOT EXISTS
(SELECT*
FROM SC SCY
WHERE SCY.Sno='1042'AND NOT EXISTS
(SELECT *
FROMSCSCZ
WHERE SCZ.Sno=SCX.Sno AND SCZ.Cno=SCY.Cno));与该查询等价的元组演算表达式为{t|(13)(SC(u)∧SC(v)∧(14)∧t[1]= u[1])}。
A.
B.
C.
D.