Question

我有几个工作表，我正在合并到一个将用于显示的决赛桌。如果显示表不包含从工作表（以下称为src）编译的主键，那么我将该行插入显示。这很好用，下一部分让我感到困惑。

如果主键已经显示，我只想更新显示行，如果src行具有相同的主键但至少有一列与显示行不同。我想使用MD5算法使用HASHBYTES（）方法实现它。

从msdn，语法应如下所示：HASHBYTES('MD5', {@variable | 'string'})

我希望能够在我的合并声明中做到这样的事情：

WHEN MATCHED AND HASHBYTES('MD5', display) != HASHBYTES('MD5', src) THEN ...(stuff)

如何完成HASHBYTES功能？

这是我当前的合并声明

MERGE dbo.DisplayCases AS display
USING (SELECT CaseId, Title, projects.ProjectName, categories.CategoryTitle, Root, milestones.MilestoneName,
        milestones.MilestoneDate, Priority, statuses.StatusTitle, EstimatedHours, ElapsedHours, personAssigned.Name as AssignedTo,
        personResolved.Name as ResolvedBy, cases.IsResolved, IsOpen, Opened, Resolved, Uri, ResolveUri,
        OutlineUri, SpecUri, ParentId, Backlog
        FROM fogbugz.Cases cases
        JOIN fogbugz.Projects projects ON cases.ProjectId = projects.ProjectId
        JOIN fogbugz.Categories categories ON cases.CategoryId = categories.CategoryId
        JOIN fogbugz.Milestones milestones ON cases.MilestoneId = milestones.MilestoneId
        JOIN fogbugz.Statuses statuses ON cases.Status = statuses.StatusId
        JOIN fogbugz.People personAssigned ON cases.AssignedTo = personAssigned.Id
        LEFT JOIN fogbugz.People personResolved ON cases.ResolvedBy = personResolved.Id
        ) as src
ON display.CaseId = src.CaseId
WHEN NOT MATCHED THEN
    INSERT(CaseId, CaseTitle, ProjectName, CategoryTitle, RootId, MilestoneName, MilestoneDate, Priority,
        StatusTitle, EstHrs, ElapsedHrs, AssignedTo, ResolvedBy, IsOpen, IsResolved, Opened, Resolved, Uri,
        ResolveUri, OutlineUri, Spec, ParentId, Backlog)
    VALUES(src.CaseId, src.Title, src.ProjectName, src.CategoryTitle, src.Root, src.MilestoneName,
        src.MilestoneDate, src.Priority, src.StatusTitle, src.EstimatedHours, src.ElapsedHours,
        src.AssignedTo, src.ResolvedBy, src.IsResolved, src.IsOpen, src.Opened, src.Resolved,
        src.Uri, src.ResolveUri, src.OutlineUri, src.SpecUri, src.ParentId, src.Backlog);

Answer 1

来自Martin Smith的评论......

你可以WHEN MATCHED AND EXISTS(SELECT Source.* EXCEPT SELECT Target.*) THEN UPDATE ...

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