數(shù)據(jù)庫習(xí)題作業(yè)(編輯修改稿)
2025-04-21 02:56 本頁面
【文章內(nèi)容簡介】 T C．COUNT(S)FROM SCGROUP BY CHAVING COUNT(*)10ORDER BY 2 DESC，1；⑤檢索學(xué)號比WANG同學(xué)大，而年齡比他小的學(xué)生姓名。SELECT SNAMEFROM SWHERE SALL(SELECT S FROM SWHERE SNAME=’WANG’)AND AGEALL( SELECT AGEFROM SWHERE SNAME=’WANG)；⑥在表SC中檢索成績?yōu)榭罩档膶W(xué)生的學(xué)號和課程號。SELECT S, CFROM SCWHERE SCORE IS NULL；⑦檢索姓名以L開頭的所有學(xué)生的姓名和年齡。SELECT SNAME, AGEFROM SWHERE SNAME LIKE ’L％’。⑧求年齡大于女同學(xué)平均年齡的男學(xué)生的姓名和年齡。SELECT SNAME, AGEFROM SWHERE SEX=’M’AND AGE(SELECT AVG(AGE)FROM SWHERE SEX=’F’)；⑨求年齡大于所有女同學(xué)年齡的男學(xué)生的姓名和年齡。SELECT SNAME, AGEFROM SWHERE SEX=‘M’AND AGEALL(SELECT AGEFROM SWHERE SEX=’F’)；【3．12】解：①INSERT INTO CVALUES(‘C8’，’VC++’，’T6’)；②法一：INSERT INTO FACULTY(TNAME)SELECT DISTINCT TNAMEFROM (SELECT TNAME，C．C，AVG(SCORE) FROM T, C, SC WHERE T．T=C．T AND C．C=SC．C GROUP BY TNAME，C．C) AS RESULT(TNAME，C，AVG—SCORE) AS XWHERE 80=ALL(SELECT AVG—SCORE FROM RESULT AS Y WHERE Y．TNAME=X．TNAME)；法二INSERT INTO FACULTY(TNAME)SELECT DISTINCT TNAMEFROM T, C, SC WHERE C．C=SC．C AND T．T=C．TAND T NOT IN (SELECT T FROM C WHERE C IN (SELECT C FROM SC GROUP BY C HAVING AVG(SCORE)=80))③DELETE FROM SC WHERE SCORE IS NULL；④DELETE FROM SC WHERE S IN(SELECT S FROM S WHERE SEX=’F’) AND C IN(SELECT C FROM C, T WHERE = AND TNAME=’LIU’)。⑤UPDATE SC SET SCORE=60 WHERE SCORE60 AND C IN(SELECT CFROM C WHERE CNAME=’MATHS’)；⑥UPDATE SC SET SCORE=SCORE * WHERE S IN(SELECT S FROM S WHERE SEX=39。F’) AND SCORE(SELECT AVG(SCORE) FROM SC)；⑦用兩個(gè)UPDATE語句實(shí)現(xiàn)：UPDATE SCSET SCORE=SCORE * WHERE C=’C4’AND SCORE70；UPDAT
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