在Visual F0xPro巾为学生表xs.DBF建立视图sT,其中包含职称字段zc和姓名字段xM.可执行以下命令()
A. CREATE TABLE ST AS SELECTXM,ZC FR()MXS
B. CREATE VIEW ST AS SELECTXM,ZC FROM XS
C. REATE DATABASE ST AS SE-I.ECT XM,ZC FROM XS
D. CREATE TNDEX ST AS SELECTXM.ZC FROM XS
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若要查询Kc表中的xF字段,并要求不能有重复,则sQI.语句为()
A. SELECT*FROM KC
B. SEI,ECT AI.I.XF FROM KC
C. SELECT DISTICT XF FROM KC
D. SELECT XF FROM KC
简述冯·诺伊曼体系结构构成的计算机必须具有的功能.到(%)简述多媒体技术具有的特征
在SQL SERVER中,查询STUDENTl表XB为空的记录l贝0 SQL语句为()
A. SEI.ECT X FROM STUDENTlWHERE XBIS NOTNULL
B. SELECT*FROM STUDENTlWHERE XBISNULL
C. SELECT*FROM STUDENTlWHERE XB-NULL
D. 以上都不是