Question

我的桌子每位员工每年有一条记录。如何为每位员工选择一条记录，以获得该员工的最新一年？

列为employee_ref, firstname, lastname, employment_year。

每个employee_ref都会有多条记录，每条记录都有employment_year

的不同值

我想为每个employee_ref选择一条记录，其中employment_year具有该employee_ref的最高值，并显示此记录中的firstname和lastname

虽然我知道SQL，但我的技能并不适合这个。

Answer 1

您可以使用子选择执行此操作：

SELECT employee_ref, firstname, lastname
FROM table
WHERE employment_year = (
    SELECT MAX(employment_year)
    FROM table b
    WHERE b.employee_ref = table.employee_ref)

Answer 2

这样的事情应该有效。

select firstname, lastname, maxyear
from table join (
select employee_ref, max(employment_year) maxyear
from table
group by employee_ref) temp on table.employee_ref = temp.employee_ref
and employment_year = maxyear

Answer 3

假设employment_year是一个整数，你可以做类似的事情：

SELECT TOP 1 * from (select * from employee where employment_ref=x order by employment_year)

有关详细信息，请参阅here。

Answer 4

这应该有效：

with EmployeesMostRecentYear as 
(
SELECT [Employee_ref]
  ,[firstname]
  ,[lastname]
  ,[employment_year]
  ,ROW_NUMBER() over (partition by [Employee_ref],[firstname],[lastname] order by [employment_year] desc) as YearIndex
FROM [TestDb].[dbo].[Employees] E 
)
select * from EmployeesMostRecentYear
where YearIndex = 1

表每位员工每年有一条记录。如何为该员工选择最近一年的每位员工的记录？

4 个答案: