ept
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o
oti
selectdept
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十二、在一个表中查找与其他表不匹配的记录db2mysqlpostgresqlsqlserverselectdfromdeptdleftouterjoi
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ddept
oedept
owhereedept
ois
ulloracleselectdfromdeptdempewhereddept
oedept
oa
dedept
ois
ull
十三、向查询中增加联接而不影响其他联接db2mysqlpostgresqlsqlserverselectee
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deptdo
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十四、检测两个表中是否有相同的数据解决原理：1、首先，查找处表emp中存在而视图v中没有的行2、然后合并（u
io
all）在视图v中存在，而在表emp中没有的行
十五、识别和消除笛卡尔积在from子句对表进行联接来返回正确的结果集：selectee
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o
十六、聚集与联接只对不相同的工资求和mysqlpostgresqlselectdept
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usebwhereeemp
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oa
dedept
o10x
十七、聚集与外联接只对部门10中不同的工资进行汇总db2mysqlpostgresqlsqlserverselectdept
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ctsalastotal_salsumbo
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