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SELECT * FROM (SELECT ROW_NUMBER() OVER (PARTITION BY H.ALARMINDEX ORDER BY H.HANDLETIME DESC) N,
H.* FROM M_ALARMHANDLE H) M
WHERE M.N=1
SELECT ROW_NUMBER() OVER (PARTITION BY H.ALARMINDEX ORDER BY H.HANDLETIME DESC) N, H.* FROM M_ALARMHANDLE H，这个语句就是用于分组 排序的语句，后面的where M.N=1是取得分组排序后组中第一行，
select HANDLELSH,ALARMINDEX,HANDLESTATUS,HANDLETIME,HANDLEPERSON,HANDLEDESCRIPTION,HANDLETYPE,rank from ( select H.*,@rownum:=@rownum+1 , if(@Group=H.ALARMINDEX,@rank:=@rank+1,@rank:=1) as rank, @Group:=H.ALARMINDEX from ( select * from M_ALARMHANDLE order by HANDLETIME DESC ) H ,(select @rownum :=0 , @Group := null ,@rank:=0) a ) result where rank=1;
var M_ALARMHANDLEList = (from HA in dbManager.M_ALARMHANDLE
group HA by HA.ALARMINDEX into HH
from MH in HH
orderby MH.HANDLETIME descending
select new
{
RowNo = RowNo+1,
MH.HANDLELSH,
MH.HANDLEDESCRIPTION,
MH.HANDLEPERSON,
MH.HANDLESTATUS,
MH.HANDLETIME,
MH.HANDLETYPE,
MH.ALARMINDEX
}).Where(m=>m.RowNo==1);
drop table if exists Wmy; create table Wmy (id int ,GroupId int ,salary decimal(10,2) ); insert into Wmy values (1,10,5500.00), (2,10,4500.00), (3,20,1900.00), (4,20,4800.00), (5,40,6500.00), (6,40,14500.00), (7,40,44500.00), (8,50,6500.00), (9,50,7500.00); select id,GroupId,salary,rank from ( select H.id,H.GroupId,H.salary,@rownum:=@rownum+1 , if(@Group=H.GroupId,@rank:=@rank+1,@rank:=1) as rank, @Group:=H.GroupId from ( select id,GroupId,salary from Wmy order by GroupId asc ,salary desc ) H ,(select @rownum :=0 , @Group := null ,@rank:=0) a ) result;
My SQL和LINQ 实现ROW_NUMBER() OVER
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原文地址：http://www.cnblogs.com/wangboke/p/5669277.html
