A.select avg(price),type from book group by type B.select count(price),type from book group by price C.select avg(price),type from book group by price D.select count(price),type from book group by type
A.selec tright(’hello’,3)返回值為:hel B.selec tltrim(rtrim(’hello’))返回值為:hello(前后都無空格) C.selec treplace(’hello’,’e’,’o’)返回值為:hollo D.selec tlen(’hello’)返回值為:5
A.數(shù)據(jù)庫在磁盤上默認(rèn)的存儲(chǔ)位置是:SQL Server安裝路徑\Microsoft SQL Server\MSSQL\Data B.一個(gè)數(shù)據(jù)庫至少應(yīng)包含一個(gè)數(shù)據(jù)庫文件(*.mdf)和一個(gè)事務(wù)日志文件(*.ldf) C.只有當(dāng)數(shù)據(jù)庫中不存在數(shù)據(jù)的情況下,才可以進(jìn)行數(shù)據(jù)庫的收縮操作。 D.可以通過從A機(jī)器拷貝數(shù)據(jù)庫文件和事務(wù)日志文件至B機(jī)器,然后通過在B機(jī)器上執(zhí)行相應(yīng)的附加數(shù)據(jù)庫操作,實(shí)現(xiàn)數(shù)據(jù)庫從A機(jī)器到B機(jī)器的復(fù)制。