根据列值删除重复行答案

【问题标题】：Removing duplicate rows based on column value根据列值删除重复行
【发布时间】：2019-05-29 12:18:14
【问题描述】：

我有一个下面的查询，它正在工作，但对于同一属性 ROADLOG/HPMS，NRLG_SMAINT 的某些属性不是 Y，我想删除重复的行。我不介意任何 NRLG_SMAINT 属性不是 Y，但如果是 Y，我不希望该行显示为相同的 ROADLOG/HPMS 属性，其中有 Y。查询如下：

select t.nrlg_dept_route || t.nrlg_dept_roadbed as roadlog,s.HPMS,t.nrlg_smaint
from TIS.TIS_NEW_ROADLOG t right join HPMS_DATA s
on t.nrlg_dept_route || t.nrlg_dept_roadbed = s.hpms
group by t.nrlg_dept_route || t.nrlg_dept_roadbed,s.HPMS,t.nrlg_smaint
order by 1

这是迄今为止的输出示例：

                ROADLOG       HPMS      NRLG_SMAINT
          85    C001821N    C001821N    
          86    C001992N    C001992N    
          87    C005201N    C005201N    Y
          88    C005201N    C005201N    --- remove this row
          89    C005202E    C005202E    Y
          90    C005202E    C005202E    --- remove this row
          91    C005203N    C005203N    Y
          92    C005203N    C005203N    --- remove this row
          93    C005205N    C005205N    Y
          94    C005205N    C005205N    
          95    C005207S    C005207S    --- leave this row
          96    C005208N    C005208N    Y
          97    C005208N    C005208N    
          98    C005209N    C005209N    Y
          99    C005209N    C005209N

【问题讨论】：

第 94 行和第 99 行呢？
您将删除第 94,97 和 99 行。我只是放入离开行并删除行文本以帮助说明这一点。但留下 85,86。

标签： sql oracle11g plsqldeveloper

【解决方案1】：

我想你想修复聚合：

select t.nrlg_dept_route || t.nrlg_dept_roadbed as roadlog,
       s.HPMS,
       max(t.nrlg_smaint) as nrlg_smaint
from  HPMS_DATA s left join
      TIS.TIS_NEW_ROADLOG t 
      on t.nrlg_dept_route || t.nrlg_dept_roadbed = s.hpms
group by t.nrlg_dept_route || t.nrlg_dept_roadbed, s.HPMS
order by 1

【讨论】：

是的，已修复，但我必须删除正确的连接。