Question

我希望在从另一列中减去一列后找到MAX值。我目前所用的语法似乎不起作用。

SELECT
    [EmpName] as 'Employee Name',
    MAX([EndYear]-[BeginYear]) as 'Total Years'
FROM
    [dbo].[EMPLOYEE];

Answer 1

使用RANK声明。

SELECT *, 
    RANK() OVER (PARTITION BY [Employee Name] ORDER BY [Total Years] DESC) AS Ranking
FROM
(
    SELECT EmpName AS 'Employee Name', EndYear - BeginYear AS 'Total Years'
    FROM Employee
) TotalYears
WHERE Ranking = 1

请记住，我还没有真正测试过上面的SQL，我只是从内存中编写它。我现在要启动一个数据库来检查语法。

Answer 2

Max语句必须处理聚合数据，因此请添加一个组。

SELECT
    [EmpName] as 'Employee Name',
    MAX([EndYear]-[BeginYear]) as 'Total Years'
FROM
    [dbo].[EMPLOYEE]
group by EmpName;

Answer 3

你可以沿着这些方向使用......

;WITH emps AS (
    SELECT 
        [EmpName] AS 'EmployeeName',
        [EndYear] - [Begin Year] AS 'TotalYears'
    FROM    
        [dbo].[Employee]
)

SELECT * FROM emps WHERE TotalYears = (SELECT MAX(TotalYears) FROM emps)

MAX的SQL语法

3 个答案: