Sql 如何修改要执行的查询？

我有以下查询，我希望它显示“Not-Yet”，而不是显示数据库中Status列的NULL值怎么做？

SELECT     dbo.SafetySuggestionsLog.Title, dbo.SafetySuggestionsLog.Description, dbo.SafetySuggestionsLog.Username, dbo.SafetySuggestionsStatus.Status,
                 CASE WHEN dbo.SafetySuggestionsStatus.Status  IS NULL THEN 'NOT YET'
FROM         dbo.SafetySuggestionsLog INNER JOIN
                      dbo.employee ON dbo.SafetySuggestionsLog.Username = dbo.employee.Username LEFT OUTER JOIN
                      dbo.SafetySuggestionsStatus ON dbo.SafetySuggestionsLog.StatusID = dbo.SafetySuggestionsStatus.ID
WHERE     (dbo.employee.Username = @Username)

供您参考，该数据库设计如下所示：

Employee Table: Username, Name
SafetySuggestionsLog Table: ID, Title, Description, Username, StatusID
SafetySuggestionsStatus: ID, Status

使用或

或

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你说得很对，可以使用ISNULL或CASE

CASE WHEN dbo.Blah.Status IS NULL THEN 'Not Yet' ELSE dbo.Blah.Status END

或

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您是否检查了CASE-WHEN子句的语法？@PanagiotisKanavos

COALESCE

更好：）并删除格式错误的CASE-WHEN，因为它会阻止查询编译您假设代码不包含

ELSE-Status-END

。（尽管这可能是一个正确的假设）为了防止有人想知道ISNULL和COALESCE之间的区别，COALESCE从传递给它的参数返回第一个非null值，而ISNULL返回原始值或替换值（如果需要）NULL@ypercube-不，对于2个参数，它们并不总是等效的<代码>声明@X字符（1）；选择ISNULL（@X，'Foo'）、COALESCE（@X，'Foo'）返回

（F，Foo）

SELECT     dbo.SafetySuggestionsLog.Title, dbo.SafetySuggestionsLog.Description, dbo.SafetySuggestionsLog.Username, ISNULL(dbo.SafetySuggestionsStatus.Status, "Not Yet") as 'Status'
FROM         dbo.SafetySuggestionsLog INNER JOIN
                      dbo.employee ON dbo.SafetySuggestionsLog.Username = dbo.employee.Username LEFT OUTER JOIN
                      dbo.SafetySuggestionsStatus ON dbo.SafetySuggestionsLog.StatusID = dbo.SafetySuggestionsStatus.ID
WHERE     (dbo.employee.Username = @Username)

CASE WHEN dbo.Blah.Status IS NULL THEN 'Not Yet' ELSE dbo.Blah.Status END

isnull(dbo.Blah.Status, 'Not Yet')