我在MySQL 5.6中尝试以下SQL:
select Test=1 from ALL_FILES_INFO;
但是我收到了一个错误。
错误代码:1054。“字段列表”中的未知列“测试”
这是像这样的事情
Select Name,
Amount=(select Amount from EmployeeAmount where EmployeeName=Name)
from Employee;
相同的代码在Microsoft SQL Server中正常运行。
答案 0 :(得分:2)
SQL Server有一种说明列别名的替代方法,据我所知,这可以完全相同,并且可以在MySQL和SQL Server上运行;
SELECT 1 AS Test from ALL_FILES_INFO;
答案 1 :(得分:1)
加入表格比使用相关子查询更好:
SELECT Employee.Name, EmployeeAmount.Amount
FROM Employee
JOIN EmployeeAmount ON EmployeeAmount.EmployeeName = Employee.Name