Mysql SQL子查询问题3

我的SQL代码有问题

当我运行这段代码时，我得到这样的错误消息：

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子查询返回了多个值。这是不允许的，因为 子查询后面是=，！=，=或者当子查询用作 表情

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我不知道如何更正此代码以运行它

有人能帮我看看吗

谢谢你的帮助

SELECT dbo.FRA$.[GUID], dbo.FRA$.[Last Name], 

dbo.FRA$.[First Name], dbo.FRA$.[HR Manager Last Name], 

dbo.FRA$.[HR Manager First Name], (SELECT dbo.FRA$.[Business Email Address] FROM dbo.FRA$ t WHERE t.[HR Manager ID] = t.[Emplid]) AS [HR Manager E-Mail],

dbo.LOC.Descr AS [COMPANY NAME], dbo.FRA$.[Location Code],

dbo.LOC.[ADDRESS], dbo.LOC.Postal, dbo.LOC.City, dbo.FRA$.[National ID], dbo.FRA$.[Current Employee Class Desc] AS [Current Empl Class],

dbo.FRA$.[Contract type description] AS [CONTRACT TYPE], dbo.FRA$.[Business Title],

CASE dbo.FRA$.[Current Employee Class Desc]
WHEN 'Operator' THEN 10
WHEN 'Clerical worker' THEN 22
WHEN 'Technician' THEN 32
WHEN 'Supervisor' THEN 33
WHEN 'Manager&Engineer' THEN 54
END AS [Salary brutto],

FORMAT(dbo.FRA$.[Birthdate],'yyyy-MM-dd') AS [Birth Date], FORMAT(dbo.FRA$.[Last Start Date],'yyyy-MM-dd') AS [Hire Date]

FROM dbo.FRA$  

INNER JOIN dbo.LOC 

ON dbo.FRA$.[Location Code] = dbo.LOC.[Location]

WHERE [HR Status] IN ('International Assignment','Active','Leave of Absence');

试着替换

SELECT dbo.FRA$.[Business Email Address] FROM dbo.FRA$ t WHERE t.[HR Manager ID] = t.[Emplid]

与

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从子查询返回的行中只取一行

您好，谢谢您的帮助。我试过了，结果代码显示的是员工的电子邮件，而不是人力资源经理的电子邮件地址？你好，米雷克。我编辑了我的答案。您应该将子查询表中的t[Emplid]绑定到Main表中的[HR Manager ID]。只要去掉t。或者最好为主表创建一个别名。您好，Dmitry，我已更正为从dbo.FRA$t中选择排名前1的dbo.FRA$.[Business Email Address]，其中dbo.FRA$.[HR Manager ID]=t.[Emplid]作为[HR Manager E-Mail]，但仍然从员工而不是人力资源经理那里收到电子邮件？甚至问题可以在SELECT dbo.FRA$.[Business Email Address]中。可能您需要使用别名t来选择t.[Business Email Address]Mirek，我做了一些编辑，最后尝试从dbo.FRA$t中选择TOP 1 t.[Business Email Address]，其中[HR Manager ID]=t.[Emplid]，并且此查询应该在MySQL、MS SQL Server和Sqlite上运行？？？

SELECT TOP 1 t.[Business Email Address] FROM dbo.FRA$ t WHERE [HR Manager ID] = t.[Emplid]