从列中选择记录

Question

I have to select 100 highest records by the number from column. Structure looks like that:

---------
| A | B |
---------
| 1 | 1 |
| 22| 2 |
| 31| 1 |
| 41| 2 |
---------

I need to select for every nr B the highest numbers from column A. In this example it will be

---------
| A | B |
---------
| 31| 1 |
| 41| 2 |
---------

B1 = 31, 1; B2 = 41, 22.

The task looks quite easy, but I've got more than 10 mln numbers in column A and something like 40 000 nr in column B.

Can you please help me? I'm not really good at sql and script building :(

Answer 1

I have a similar problem into a project that I made.

You should correct the tag MySql to SQLSERVER .

I use this SQL Fiddle to make a fiddle about the problem, I think that is what you want.

MS SQL Server 2014 Schema Setup :

create table tab1 (

  a int,
  b int

);

insert into tab1 (a, b) values 
(1,1),
(22,2),
(11,3),
(31,1),
(10,3),
(41,2);

Query 1 :

SELECT TOP 100 Max(a) as a, b
FROM tab1
GROUP BY b
ORDER BY b asc

Results :

|  a | b |
    |----|---|
    | 31 | 1 |
    | 41 | 2 |
    | 11 | 3 |

Answer 2

As far as i understood, I guess this could help

Select Top 10 A , B from tableName group by B , A

this will give you the following

---------
| A | B |
---------
| 1 | 1 |
| 31| 1 |
| 22| 2 |
| 41| 2 |
---------