标题 | Oracle minus使用 |
范文 | 新建两个表: create table guotest1 ( sName varchar2(10), Gender varchar2(10) ) create table guotest2 ( sName varchar2(10), Gender varchar2(10) ) 插入数据: insert into guotest1 values('a', 'm'); insert into guotest1 values('b', 'm'); insert into guotest1 values('c', 'f'); insert into guotest1 values('d', 'f'); insert into guotest2 values('e', 'm'); insert into guotest2 values('f', 'm'); insert into guotest2 values('g', 'f'); insert into guotest2 values('h', 'f'); 1 minus返回的是两个查询结果表的差集 例如:select * from guotest1 where rownum <= 4 minus select * from guotest1 where rownum <= 2 返回结果: "SNAME","GENDER" "c","f" "d","f" 2 minus返回的记录总是来自于左边的表 例如:select * from guotest1 minus select * from guotest2 返回结果: "SNAME","GENDER" "a","m" "b","m" "c","f" "d","f" 像是说:如果左边的表中的某个记录存在于右边的表中,则该记录不会返回 |
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