Sql 根据关系类型获取最大数量

我有一个疑问：

 SELECT
                   MAX([D].[DesignKey]) AS [DesignKey]
                   FROM [Project] AS [P]
                       INNER JOIN [DesignGroup] AS [DG] ON [P].[ProjectKey] = [DG].[ProjectKey]
                       INNER JOIN [Design] AS [D] ON [DG].[DesignGroupId] = [D].[DesignGroupId]
                   GROUP BY
                          [P].[ProjectKey]
                        , [D].[Name]
                        ORDER BY DesignKey

我的关系是：一个项目可以有多个

设计组

，一个

设计

可以有多个

设计组

，但一个设计不能有多个项目

---

我想做的是选择每个

DesignGroup

的最大设计键编号，我如何才能做到这一点？在我的查询中，它返回所有的设计键，而不关心它是否是每个设计组的最后一个。关于

在分组依据和选择上使用DesignGroupId

SELECT
                  DesignGroupId, MAX([D].[DesignKey]) AS [DesignKey]
                   FROM [Project] AS [P]
                       INNER JOIN [DesignGroup] AS [DG] ON [P].[ProjectKey] = [DG].[ProjectKey]
                       INNER JOIN [Design] AS [D] ON [DG].[DesignGroupId] = [D].[DesignGroupId]
                   GROUP BY
                          DesignGroupId
                       ORDER BY DesignKey

---

这应该满足您的要求：

SELECT [DG].[DesignGroupId], MAX([D].[DesignKey]) AS [DesignKey]
FROM [DesignGroup] [DG] JOIN
     [Design] [D]
     ON [DG].[DesignGroupId] = [D].[DesignGroupId]
GROUP BY [DG].[DesignGroupId];

请注意，回答您的问题不需要

项目

表