在MySql中获取两列具有最大值的行

Question

i have a table which contains id , primaryid , data ,dataname columns i want only rows for which contains max id and primaryid

create table #temp
(
    id int,
    primaryid int,
    data   nvarchar(20),
    data_name   nvarchar(30)
)


insert into #temp
values (1,1,'3223sfd','434'),(1,2,'sdfsd','dfsdfsd'),
       (1,3,'sdfs897d','898'),(1,4,'898','545'),(1,5,'898','uuyu'),
       (2,1,'3223sfd','434'),(2,2,'sdfsd','dfsdfsd'),
       (2,3,'sdfs897d','898'),(2,4,'898','545'),(2,5,'898','uuyu')

i achieve this with below query

select T.id , T.primaryid , T.data , T.data_name from #temp T , (select ID, max(primaryid) rank from #temp t2  group by id ) as T2
where t.primaryid = t2.rank group by T.id , T.primaryid , T.data , T.data_name

but my table have more than 100k records i want to worry about that

What will be optimized query for this?

Answer 1

You may use subquery here :

select * 
from #temp t
where primaryid = (select max(tt.primaryid) from #temp tt where tt.id = t.id);

Answer 2

You appear to be using SQL Server. If so, one method is:

select top (1) with ties t.*
from #temp t
order by row_number() over (partition by id order by primaryid desc);

Answer 3

First you should create index on id and primaryid and then use join as below:

SELECT T.id , T.primaryid , T.data , T.data_name FROM #temp T
JOIN (select id, max(primaryid) as primaryid from #temp t2  group by id ) as T2
ON T.id = t2.id and t.primaryid = t2.primaryid