Mysql 1242-子查询返回超过1行1

看起来您正在尝试在子查询中选择3列，然后尝试将它们表示为单列

如果我没记错的话，你不能把三列（例如“BrndName，Modname，Capacity”）放在一列（例如“crevrtv”）中而不先连接它们，所以MySQL会通知你这个事实

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您还试图返回别名为“crevrtv”的两列

您使用了两次别名

crevrtv

，您认为为什么会出现此错误？

SELECT
dept.deptname,details.UserName,
(select CONCAT(BrndName,' - ',ModName,' - ',Capacity) from details where  Devname='PROCESSOR' ) as Processor,
(select CONCAT(BrndName,' - ',ModName,' - ',Capacity) from details where  Devname='PROCESSOR' ) as Memory
FROM
dept
LEFT JOIN details ON dept.deptcode = details.DeptCode