Question

我有一个INSERT INTO SELECT查询。在SELECT语句中，我有一个子查询，我想在其中添加一个字段中的增量数字。如果我的SELECT查询并且只返回一条记录，则此查询将正常工作，但如果它返回多行，则会在增量字段中为所有这些行插入相同的数字。有没有办法限制它每次都增加一个增量号？

INSERT INTO PM_Ingrediants_Arrangements_Temp 
(AdminID,ArrangementID,IngrediantID,Sequence)
(SELECT 
     @AdminID, @ArrangementID, PM_Ingrediants.ID, 
     (SELECT 
          MAX(ISNULL(sequence,0)) + 1 
      FROM
          PM_Ingrediants_Arrangements_Temp 
      WHERE 
          ArrangementID=@ArrangementID)
FROM 
    PM_Ingrediants 
WHERE 
    PM_Ingrediants.ID IN (SELECT 
                              ID 
                          FROM 
                              GetIDsTableFromIDsList(@IngrediantsIDs))
)

Answer 1

您可以使用row_number()功能。

INSERT INTO PM_Ingrediants_Arrangements_Temp(AdminID, ArrangementID, IngrediantID, Sequence)
    SELECT @AdminID, @ArrangementID, PM_Ingrediants.ID,
            row_number() over (order by (select NULL))
    FROM PM_Ingrediants 
    WHERE PM_Ingrediants.ID IN (SELECT ID FROM GetIDsTableFromIDsList(@IngrediantsIDs)
                             )

如果您想从表中已有的最大值开始，请执行以下操作：

INSERT INTO PM_Ingrediants_Arrangements_Temp(AdminID, ArrangementID, IngrediantID, Sequence)
    SELECT @AdminID, @ArrangementID, PM_Ingrediants.ID,
           coalesce(const.maxs, 0) + row_number() over (order by (select NULL))
    FROM PM_Ingrediants cross join
         (select max(sequence) as maxs from PM_Ingrediants_Arrangement_Temp) const
    WHERE PM_Ingrediants.ID IN (SELECT ID FROM GetIDsTableFromIDsList(@IngrediantsIDs)
                             )

最后，您可以将sequence列设置为自动递增标识列。这样就不需要每次都增加它：

create table PM_Ingrediants_Arrangement_Temp ( . . .
    sequence int identity(1, 1) -- and might consider making this a primary key too
    . . .
)

在SQL Server中的INSERT INTO SELECT查询中的字段中添加增量编号

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