多項選擇題數(shù)據(jù)庫中有一張表名稱為Student,有列Number,Name,Age,IDCard,Sex。主鍵為Number。統(tǒng)計學生總人數(shù),下列哪個SQL語句是正確的()

A.Select Count(1)From Student
B.Select Sum(*)From Student
C.Selec tAvg(*)From Student
D.Select Count(*)From Student


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2.多項選擇題數(shù)據(jù)庫中有一張表名為Emp,包含有如下列:EmpNO(雇員編號,Varchar(20),Pk),Job(職位Varchar(10)),HirDate(雇傭日期,Date),Sal(月薪,F(xiàn)loat)。查詢出職位不為“辦事員”的雇員信息是()

A.Select *From Emp Where Job>="辦事員"
B.Select* From Emp Where Job==’辦事員’
C.Select* From Emp Where Job<>’辦事員’
D.Select* From Emp Where Job!=’辦事員’

3.多項選擇題數(shù)據(jù)庫中有一張表名為Emp,包含有如下列:EmpNO(雇員編號,Varchar(20),Pk),Job(職位Varchar(10)),HirDate(雇傭日期,Date),Sal(月薪,F(xiàn)loat)。查詢出受雇于1981年的雇員信息是()

A.elect * From Emp Where HirDate>='1981-1-1' And HirDate <='1981-12-31'  
B.Select * From Emp Where Between In '1981-1-1' And <'1981-12-31'
C.Select * From Emp Where Between In '1981-12-31' And <'1981-1-1'  
D.Select * From Emp Where HirDate>='1981-1-1' NOT HirDate <='1981-12-31'

4.多項選擇題數(shù)據(jù)庫中有一張表名為Emp,包含有如下列:EmpNO(雇員編號,Varchar(20),Pk),Job(職位Varchar(10)),HirDate(雇傭日期,Date),Sal(月薪,F(xiàn)loat),Comm(獎金,F(xiàn)loat,可為空)。查詢出雇員編號為791,792,793的雇員信息是()

A.Select * From Emp Where EmpNO  In('791','792','793') 
B.Select * From Emp Where EmpNO ='791' Or EmpNO='792' OR EmpNO='793' 
C.Select * From Emp Where EmpNO >='791' And EmpNO<='793' 
D.Select * From Emp Where EmpNO >'791' And EmpNO<'793'

5.多項選擇題數(shù)據(jù)庫中有一張表名為Emp,包含有如下列:EmpNO(雇員編號,Varchar(20),Pk),Job(職位Varchar(10)),HirDate(雇傭日期,Date),Sal(月薪,F(xiàn)loat),Comm(獎金,F(xiàn)loat,可為空)。查詢出雇員編號不為791,792,793的雇員信息應該是用哪些數(shù)據(jù)查詢?()

A.Select * From Emp Where EmpNO Not In('791','792','793') 
B.Select * From Emp Where EmpNO !='791' AND EmpNO!='792' And EmpNO='793' 
C.Select * From Emp Where EmpNO <>'791' AND EmpNO<>792' And EmpNO=<>793' 
D.Select * From Emp Where EmpNO =!'791' AND EmpNO =!'792' And EmpNO =!'793'