SQL查找按字段分组且组中最小的所有该表的所有属性

①利用临时表，先存储按分组和每组最小的数据，再和表连接，查找表所有属性

create table #array (EmployeeID int,min_OrderID int)

insert #array select EmployeeID,min(OrderID) from orders group by EmployeeID

select * from #array

select   *   from  orders,#array 

where orders.EmployeeID=#array.EmployeeID 

and orders.OrderID=#array.min_OrderID

drop table #array

②用别名分组和每组，再和表连接，查找表所有属性

select * 

from orders,

(select EmployeeID,min(OrderID) as min_OrderID from orders group by EmployeeID)

 as MinTable 
Where orders.EmployeeID = MinTable.EmployeeID  

and orders.OrderID=MinTable.min_OrderID

order   by  EmployeeID   desc