SQL - 用其他数据替换返回的数据

Question

我正在使用以下 SQL 语法检索数据：

SELECT TOP 5 EventId, EventTime, DeviceName, Comment, Tenant, TenantName, Individual, 
                InetDb.dbo.Individuals.FirstName, InetDb.dbo.Individuals.LastName, InetDb.dbo.IndivImages.UserImage
                FROM taclogdata.dbo.Event
                LEFT JOIN InetDb.dbo.Tenants
                    ON taclogdata.dbo.Event.Tenant = InetDb.dbo.Tenants.TenantId
                LEFT JOIN InetDb.dbo.Individuals
                    ON taclogdata.dbo.Event.Individual = InetDb.dbo.Individuals.IndivId 
                    AND taclogdata.dbo.Event.Tenant = InetDb.dbo.Individuals.TenantNdx
                LEFT JOIN InetDb.dbo.IndivImages
                    ON InetDb.dbo.Individuals.IndivId = InetDb.dbo.IndivImages.IndivNdx
                    AND InetDb.dbo.Individuals.TenantNdx = InetDb.dbo.IndivImages.TenantNdx
                WHERE (taclogdata.dbo.Event.EventTime  > DATEADD(hh, -3, GETDATE())AND taclogdata.dbo.Event.EventTime < GETDATE())
                    AND (taclogdata.dbo.Event.Comment='Reader entry' OR taclogdata.dbo.Event.Comment='Reader exit')
                    AND (taclogdata.dbo.Event.DeviceName = 'L9 1/4/1' 
                        OR taclogdata.dbo.Event.DeviceName='L1 2/1/1-2 MainD'
                        OR taclogdata.dbo.Event.DeviceName='L1 2/1/3-4 MainD'
                        OR taclogdata.dbo.Event.DeviceName='L1 2/6/1-2 Stair'
                        OR taclogdata.dbo.Event.DeviceName='L1 2/2/1-2 FDT1')
                ORDER BY taclogdata.dbo.Event.EventTime DESC

此代码运行良好，但我正在尝试简化结果。
我试图通过替换例如 DeviceName 值来简化查询返回的内容。 L1 2/1/3-4 MainD 到 Main Door 显示结果时（不替换数据库中的实际数据）

请问我该如何实现？
在此先感谢，
J

Answer 1

试试这个使用替换功能

SELECT TOP 5 EventId, EventTime, replace(DeviceName,'L1 2/1/3-4 MainD','L1 2/1/3-4 Main Door') as DeviceName, Comment, Tenant, TenantName, Individual, 
                InetDb.dbo.Individuals.FirstName, InetDb.dbo.Individuals.LastName, InetDb.dbo.IndivImages.UserImage
                FROM taclogdata.dbo.Event
                LEFT JOIN InetDb.dbo.Tenants
                    ON taclogdata.dbo.Event.Tenant = InetDb.dbo.Tenants.TenantId
                LEFT JOIN InetDb.dbo.Individuals
                    ON taclogdata.dbo.Event.Individual = InetDb.dbo.Individuals.IndivId 
                    AND taclogdata.dbo.Event.Tenant = InetDb.dbo.Individuals.TenantNdx
                LEFT JOIN InetDb.dbo.IndivImages
                    ON InetDb.dbo.Individuals.IndivId = InetDb.dbo.IndivImages.IndivNdx
                    AND InetDb.dbo.Individuals.TenantNdx = InetDb.dbo.IndivImages.TenantNdx
                WHERE (taclogdata.dbo.Event.EventTime  > DATEADD(hh, -3, GETDATE())AND taclogdata.dbo.Event.EventTime < GETDATE())
                    AND (taclogdata.dbo.Event.Comment='Reader entry' OR taclogdata.dbo.Event.Comment='Reader exit')
                    AND (taclogdata.dbo.Event.DeviceName = 'L9 1/4/1' 
                        OR taclogdata.dbo.Event.DeviceName='L1 2/1/1-2 MainD'
                        OR taclogdata.dbo.Event.DeviceName='L1 2/1/3-4 MainD'
                        OR taclogdata.dbo.Event.DeviceName='L1 2/6/1-2 Stair'
                        OR taclogdata.dbo.Event.DeviceName='L1 2/2/1-2 FDT1')
                ORDER BY taclogdata.dbo.Event.EventTime DESC

Answer 2

这里是我的建议：

如果您可以替换 SELECT 中的数据，例如：

SELECT REPLACE(DeviceName,N'2/1/3-4 MainD',N'Main Door')

如果你有很多替换，我建议创建一个临时表，加入它并从临时表中取出替换。

Answer 3

评论太长了。

您问题的具体答案是使用REPLACE() 或CASE 语句。但是，您还应该将 WHERE 子句更改为使用 IN 并使用表别名，以便代码更易于编写和阅读：

FROM taclogdata.dbo.Event e LEFT JOIN
     InetDb.dbo.Tenants t
     ON e.Tenant = t.TenantId LEFT JOIN
     InetDb.dbo.Individuals i
     ON e.Individual = i.IndivId AND e.Tenant = i.TenantNdx LEFT JOIN
     InetDb.dbo.IndivImages ii
     ON i.IndivId = ii.IndivNdx AND Ii.TenantNdx = ii.TenantNdx 
WHERE (e.EventTime  > DATEADD(hour, -3, GETDATE()) AND 
       e.EventTime < GETDATE()
      ) AND
      e.Comment IN ('Reader entry', 'Reader exit') AND
      e.DeviceName IN ('L9 1/4/1', 'L1 2/1/1-2 MainD', 'L1 2/1/3-4 MainD',
                       'L1 2/6/1-2 Stair', 'L1 2/2/1-2 FDT1'
                      )