Sql 仅选择完整集

我只想从每种类型中选择至少有一行的值

File|Value          |Type  
001 |"Crektolap"    |1  
001 |"123.45"       |2  
001 |"0.00"         |4  
002 |"Cream floure" |1  
002 |"56.89"        |2  
002 |"Supercat"     |3  
002 |"0.01"         |4  

有：1、2、3、4种类型

我想要的结果是：

File|Value          |Type  
002 |"Cream floure" |1  
002 |"56.89"        |2  
002 |"Supercat"     |3  
002 |"0.01"         |4 

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这甚至可以在一个查询中实现吗？

您可以使用窗口函数实现这一点：

select file, value, type
from (select t.*, max(dr) over (partition by file) as numtypes
      from (select t.*, dense_rank() over (partition by file order by type) as dr
            from table t
           ) t
     ) t
where numtypes = 4;

稠密_秩统计每行上枚举的不同类型值的数量。max然后获得最大值，外部查询选择有四种类型的行

如果您不知道类型的数量：

select file, value, type
from (select t.*, max(dr) over (partition by file) as numtypes
      from (select t.*, dense_rank() over (partition by file order by type) as dr
            from table t
           ) t
     ) t
where numtypes = (select count(distinct type) from table t);

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所以你不想要文件001，因为它缺少类型3？