Stray current
Rated current
Starting current
Earth current
第1题:
设有 S ( 学号,姓名,性别 ) 和 SC ( 学号,课程号,成绩 ) 两个表,如下 SQL 语句检索选修的每门课程的成绩都高于或等于 85 分的学生的学号、姓名和性别,正确的是
A)SELECT 学号 , 姓名 , 性别 FROM s WHERE EXISTS
(SELECT * FROM sc WHERE SC. 学号 = S . 学号 AND 成绩 <=85)
B)SELECT 学号 , 姓名 , 性别 FROM s WHERE NOT EXISTS
(SELECT * FROM sc WHERE SC. 学号 = S . 学号 AND 成绩 <=85)
C)SELECT 学号 , 姓名 , 性别 FRO M s WHERE EXISTS
(SELECT * FROM sc WHERE SC. 学号 =S. 学号 AND 成绩 >85)
D)SELECT 学号 , 姓名 , 性别 FROM s WHERE NOT EXISTS
(SELECT * FROM sc WHERE SC. 学号 =S. 学号 AND 成绩 <85)
第2题:
设有关系R(A,B,C)和S(C,D),与关系代数表达式ΠA,B,D(σR,C=S.C(R×S))等价的SQL语句是______。
A.SELECT*FROMR,S WHERE R.C=S.C
B.SELECT A,B,D FROM R,S WHERE R.C=S.C
C.SELECT A,B,D FROM R,S WHERE R=S
D.SELECT A,B FROM R WHERE(SELECT D FROM S WHERE R.C=S.
第3题:
I have reached a point in my lifeI am supposed to make decisions of my own.
A whichB where C how D why
第4题:
“找出北京供应商的所有信息”的SELECT语句是
A.SELECT*FROM S WHERE CITY='京'
B.SELECT SNO,SNAME FROM S WHERE CITY='北京'
C.SELECT*FROM S WHERE CITY=北京
D.SELECT SNO,SNAME FROM S WHERE CITY=北京
第5题:
查询选修了课程号为“C2”的学生号和姓名,若用下列SQL的SELECT语句表达是,( )是错误的。 A.SELECT S.S#,SNAME FROM S WHERE S.S# =(SELECT SC.S#FROM SC WHERE C#='C2') B.SELECT S.S#,SNAME FROM S,SC WHERE S.S#=SC.S# AND C#='C2' C.SELECT S.S#,SNAME FROM S,SC WHERE S.S#=SC.S# AND C#='C2'ORDER BY S.S# D.SELECT S.S#,SNAME FROM S WHERE S.S# IN(SELECT SC.S# FROM SC WHERE C#='C2')
第6题:
( 3 2 )查询学生姓名及其所选修课程的课程号和成绩,正确的 SQL 语句是
A ) SELECT S . SNAME , SC.C# , GRADE FROM S WHERE S . S # = SC . S#
B ) SELECT S . SNAME , SC.C #, GRADE FROM SC WHERE S . S # = = SC . S#
C ) SELECT S . SNAME , SC.C# , GRADE FROM S , SC WHERE S . S# = SC . S#
D ) SELECT S . SNAME , SC.C# , GRADE FROM S , SC WHERE S .S# = SC . C#
第7题:
查询选修了课程号为“C1”的学生的姓名和年龄,若用下列SQL的SELECT语句表达 时,错误的是( )。A.SELECT SNAME,AGE FROM S WHERE S .S#=(SELECT SC.S# FROM SC WHERE C.C#=’C 1’) B.SELECT SNAME,AGE FROM S,SC WHERE S.S#=SC.S# AND SC.C#=’C 1’ C.SELECT SNAME,AGE FROM S,SC WHERE S.S#=SC.S# AND SC.C#=’CI’ ORDER B Y S.S# D.SELECT SNAME,AGE FROM S WHERE S.S#=(SELECT SC.S# FROM SC WHERE SC.C#=’C 1’)
第8题:
若要求查找‘李’姓学生的学生号和姓名,正确的SQL语句是
A.SELECT S#,SNAME FROM S WHERE SNAME='李%.'
B.SELECT S#,SNAME FROM S WHERE SNAME LIKE '李%.'
C.SELECT S#,SNAME FROM S WHERE SNAME='%.李%.'
D.SELECT S#,SNAME FROM S WHERE SNAME LIKE '%.李%.'
第9题:
若要求查找姓名中第一个字为“刘”的学生号和姓名。下面列出的SQL语句中,正确的是( )。
A.SELECT S#,SNAME FROM S WHERE SNAME='刘%.'
B.SELECT S#,SNAME FROM S WHERE SNAME='刘_'
C.SELECT S#,SNAME FROM S WHERE SNAME LIKE'刘%.'
D.SELECT S#,SNAME FROM S WHERE SNAME LIKE'刘_'
第10题:
设有关系R(A,B,C)和S(C,D)。与关系代数表达式πA,B,D(σR.C=S.C(R×S)等价的SQL语句是
A.SELECT*FROM R,S WHERE R.C=S.C
B.SELECT A,B,D FROM R,S WHERE R.C=S.C
C.SELE4T 1,2,8 FROM R,S WHERE R=S
D.SELECT A,B FROM R WHERE(SELECT D FROM S WHERE R.C=S.