SELECT DISTINCT在一個列上考慮另一列

Question

我有

    Id          Number
----------- -----------
950         20213666062
951         20213666062

我只希望每個“數字”一次，其ID最高：

    Id          Number
----------- -----------
951         20213666062

SELECT
rarN.intIdRARNomina AS Id,
rarN.chrCUIL AS Number           
FROM dbo.PVN_RAR p
        INNER JOIN dbo.PVN_RARNomina rarN ON p.intIdRAR = rarN.intIdRAR
        INNER JOIN PISCYS.dbo.SYA_UltimosContratoCliente uc ON p.intNroContrato = uc.intNroContrato
WHERE
        p.intIdRAR = 4639

Answer 1

嘗試使用簡單的GROUP BY查詢：

SELECT MAX(Id) AS Id, Number
FROM yourTable
GROUP BY Number;

在您更新的問題/查詢的上下文中：

SELECT
    MAX(rarN.intIdRARNomina) AS Id,
    rarN.chrCUIL AS Number
FROM dbo.PVN_RAR p
INNER JOIN dbo.PVN_RARNomina rarN
    ON p.intIdRAR = rarN.intIdRAR
INNER JOIN PISCYS.dbo.SYA_UltimosContratoCliente uc
    ON p.intNroContrato = uc.intNroContrato
WHERE
    p.intIdRAR = 4639
GROUP BY
    Number;

Answer 2

如果您的列多於此，則需要相關子查詢，否則僅使用max() group by才能達到所需的結果：

select t.*
from table t
where t.id = (select max(t1.id) from table t1 where t1.Number = t.Number);

但是，最新版本通過使用row_number()實現此目的。

Answer 3

另一種選擇是使用自我聯接：

select t.*
from table t
inner join (select max(id) as DID, number from table group by number) t2
on t.ID = t2.DID