sql - sql - 如何计算两行的差异？

Question

我有一张这样的桌子：

Item    ProviderId

Item1   1

Item1   2

Item2   1

Item3   1

我希望得到一张新桌子。在新表中，它只列出了item至少有两个不同ProviderIds 的 s。

所以在上面的例子中，因为只有item1两个不同的ProviderId我希望得到这样的表：

Item

Item1

我怎样才能写出声明来做到这一点？

Answer 1

你必须使用group by和having：

select item
from table
group by item
having count(distinct ProviderId)>=2

或没有distinct

select item
from tab
group by item, ProviderId
having count(1)>=2;

sql 小提琴演示

以查询为表：

select item
from (select item, ptoviderId from tabA) as tab
group by item, ProviderId
having count(1)>=2;

如果要创建新表，可以使用into：

select item
into newTable
from table
-- or (select item, ptoviderId from tabA)
group by item
having count(distinct ProviderId)>=2

Answer 2

试试这个：

 SELECT [Item]      
      FROM [TABLE_NAME]
      GROUP BY [Item]
      HAVING COUNT(DISTINCT ProviderId) >1
    GO

Answer 3

INSERT INTO <your new table> (newTableItem)
    (SELECT Item
    FROM <table>
    GROUP BY Item
    HAVING COUNT(DISTINCT ProviderId) > 1)-- or just HAVING COUNT(*) > 1 if one Item can't have two times the same ProviderId