下列关于空值的叙述中,正确的是(  )

下列关于空值的叙述中,正确的是(  )A.空值是双引号中间没有空格的值 B.空值是等于0的数值 C.空值是使用Null或空白来表示字段的值 D.空值是用空格

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根据以下材料,回答题 CellPhoneLetsYourSecretOut Yourcellphoneholdssecr

根据以下材料,回答题 CellPhoneLetsYourSecretOut Yourcellphoneholdssecretsaboutyou.Beside

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根据以下材料,回答题 MorethanaRidetoSchool TheNationalEducationAssocia

根据以下材料,回答题 MorethanaRidetoSchool TheNationalEducationAssociationclaims,"Thesc

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ManyAmericanslikebasketballbetterthanfootballbecausethelatte

ManyAmericanslikebasketballbetterthanfootballbecausethelatterissoharshthatplaye

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Withoutquestion,people'slivesinChinahaveimproveddramatically

Withoutquestion,people'slivesinChinahaveimproveddramaticallyinthepasttwodecades

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