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删除除了学号字段以外,其它字段都相同的冗余记录,只保留一条!(也就是要删除凤姐和田七中一条重复数据只留一条)
要求结果数据:
原始数据:CREATETABLEtbl_stude
tsid
umber32NOTNULL
amevarchar10DEFAULTNULLsaxvarchar10DEFAULTNULLage
umber6DEFAULTNULLPRIMARYKEYidi
serti
totbl_stude
tsid
amesaxagevalues2李四男21i
serti
totbl_stude
tsid
amesaxagevalues3张三女17i
serti
totbl_stude
tsid
amesaxagevalues4李四男12i
serti
totbl_stude
tsid
amesaxagevalues6凤姐女20i
serti
totbl_stude
tsid
amesaxagevalues5凤姐女20i
serti
totbl_stude
tsid
amesaxagevalues7田七男18i
serti
totbl_stude
tsid
amesaxagevalues1田七男18i
serti
totbl_stude
tsid
amesaxagevalues8张三男17答案:mySqlDELETEFROMstude
tWHEREsidNOTINSELECTsidFROMSELECTMINsidsidFROMstude
tGROUPBYsNamesSext
foracle:DELETEFROMstude
tWHEREsidNOTINSELECTMINsidsidFROMstude
tGROUPBYsNamesSex
查询各科成绩都及格的学员
(要求查询出参加考试的各科成绩都高于60分,不管参加了多少科考试)
要求结果:
表:CREATETABLEtbl_scoreidNUMBER10NOTNULLuser
amevarchar20DEFAULTNULLcoursevarchar20DEFAULTNULLscoreNUMBER10DEFAULTNULLPRIMARYKEYid数据:i
serti
totbl_scoreiduser
amecoursescorevalues1张三语文50i
serti
totbl_scoreiduser
amecoursescorevalues2张三数学80i
serti
totbl_scoreiduser
amecoursescorevalues3张三英语90i
serti
totbl_scoreiduser
amecoursescorevalues4李四语文70i
serti
totbl_scoreiduser
amecoursescorevalues5李四数学80i
serti
totbl_scoreiduser
amecoursescorevalues6李四英语80i
serti
totbl_scoreiduser
amecoursescorevalues7王五语文50i
serti
totbl_scoreiduser
amecoursescorevalues8王五英语70i
serti
totbl_scoreiduser
amecoursescorevalues9赵六数学90答案:selectuser
amescorfromtblwhereid
oti
selectidfromtblwherescore60
f表(MYSQL)
Stude
tsidS
ameSageSsex学生表
CREATETABLEstude
tsidvarchar10NOTNULLsNamevarchar20DEFAULTNULLsAgedatetimeDEFAULT19801012231236sSexvarchar10DEFAULTNULLPRIMARYKEYsidENGINEI
oDBDEFAULTCHARSETutf8
CoursecidC
ametid课程表CREATETABLEcoursecidvarchar10NOTNULLcNamevarchar10DEFAULTNULLtidi
t20DEFAULTNULLPRIMARYKEYcidENGINEI
oDBDEFAULTCHARSETutf8SCsidcidscore成绩表
CREATETABLEscsidvarchar10DEFAULTNULLcidr
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