Question

我想从表中删除重复（与值相同且相同）元组，但需要保持元组的最小对象ID（对象ID为pk）。

所以这是列：

来自|到|时间|距离| object_id

我可以看到通过执行

删除的正确元组数

select [from],[to],count(*)
FROM table
where [object_id] NOT IN(
    SELECT min([object_id])
      FROM table
      group by [from],[to]
      having count(*) > 1)
group by [from],[to]
having count(*) > 1

但是我想首先看到在上面的SQL上计算的object_id。

Answer 1

您可以尝试使用此功能（未经测试）......

;WITH temp AS (
    SELECT [from_id], [to_id], [object_id] = min([object_id])
    FROM table
    group by [from_id],[to_id]
    having count(*) > 1)
SELECT
    t2.[from_id],
    t2.[to_id],
    t.[object_id]
FROM 
    table t
    join temp t2 
        on t2.[from_id] = t.[from_id]
        AND t2.[to_id] = t.[to_id]
        AND t2.[object_id] != t.[object_id]

编辑：

CTE temp将使用min object_id产生所有不同的分组，你想要保留一个。

SELECT [from_id], [to_id], [object_id] = min([object_id])
FROM table
group by [from_id],[to_id]
having count(*) > 1

您还想删除其他对，这些对是来自/对，但具有不同的object_id。最后一个选择应该准确输出那些记录。

删除除一个特定元组之外的重复元组

1 个答案: