A.LIMIT
B.TOP
C.COUNT
D.SUM

A.select top3 cDiscription fromTvtype order by iprice asc
B.select cDiscription from Tvtype where max（iprice）>3
C.select top3 cDiscription from Tvtype order by iprice desc
D.selec tcDiscription max（iprice）from Tvtype order by iprice

A.select CustomerName，SalesDate from Sales group by CustomerName，SalesDate
B.select CustomerName，SalesDate from Sales order by CustomerName，SalesDate
C.select CustomerName，SalesDate from Sales group by CustomerNameorderbySalesDateDESC
D.select CustomerName，SalesDate from Sales order by CustomerName，SalesDateDESC

A.select*intocatt where from kehu
B.select*into catt from kehu
C.insert into catt select*from kehu
D.inser tinto catt from select*from kehu

A.SELECT20%2
B.SELECT2*5.0
C.SELECT20.0/2
D.SELECT20/2

A.2008-3-4
B.2005-6-1
C.2005-3-7

A.经编译过一次
B.已经保存过一次
C.已经编写过的
D.已经解释过一次

A.插入和删除数据之前
B.插入和删除数据之后
C.插入和更新数据之前
D.插入和更新数据之后

A.CHECK（（CreditLimt=0 AND Verified=0）OR（CreditLimt BETWEEN 1 AND 10000 AND Verified=1）
B.CHECK（CreditLimt BETWEEN 1 AND 10000）
C.CHECK（Verified=1 AND CreditLimt BETWEEN1 AND 10000）
D.CHECK（CreditLimt=0 ANDV erified=0）AND（CreditLimt BETWEEN 1 AND 10000 AND Verified=1）

A.维护数据的实体完整性
B.提高数据录入效率
C.限制列的取值范围
D.提高数据修改效率

A.Book-code
B.Book-name
C.Issue-dt
D.Mem-cd