1.建立表並寫入測試資料
create table tb_rank_score
city varchar(20),
score int
insert into tb_rank_score values('sz',89);
insert into tb_rank_score values('sz',76);
insert into tb_rank_score values('sz',50);
insert into tb_rank_score values('sz',89);
insert into tb_rank_score values('sz',78);
insert into tb_rank_score values('sh',90);
insert into tb_rank_score values('sh',34);
insert into tb_rank_score values('sh',78);
insert into tb_rank_score values('sh',67);
insert into tb_rank_score values('sh',76);
2.普通排名:從1開始，順序往下排
mysql> select tb_rank_score.*,@r :=@r + 1 as rank
-> from tb_rank_score,(select @r := 0) r
-> order by score desc;
| city | score | rank |
| sh | 90 | 1 |
| sz | 89 | 2 |
| sz | 89 | 3 |
| sz | 78 | 4 |
| sh | 78 | 5 |
| sz | 76 | 6 |
| sh | 76 | 7 |
| sh | 67 | 8 |
| sz | 50 | 9 |
| sh | 34 | 10 |
10 rows in set (0.00 sec)
3.並列排名:相同的值是相同的排名
mysql> select tb_rank_score.* ,
-> case
-> when @p=score then @r
-> when @p:=score then @r:=@r+1
-> end rank
-> from tb_rank_score,(select @r:=0,@p:=null)r
-> order by score desc;
| city | score | rank |
| sh | 90 | 1 |
| sz | 89 | 2 |
| sz | 89 | 2 |
| sz | 78 | 3 |
| sh | 78 | 3 |
| sz | 76 | 4 |
| sh | 76 | 4 |
| sh | 67 | 5 |
| sz | 50 | 6 |
| sh | 34 | 7 |
10 rows in set (0.00 sec)
4.分組後組內排名
mysql> select city,score,rank
-> from
-> select tb_rank_score.*,if(@p=city,@r:=@r+1,@r:=1) as rank,
-> @p:=city
-> from tb_rank_score,(select @p:=null,@r:=0)r
-> order by city,score desc
-> )s;
| city | score | rank |
| sh | 90 | 1 |
| sh | 78 | 2 |
| sh | 76 | 3 |
| sh | 67 | 4 |
| sh | 34 | 5 |
| sz | 89 | 1 |
| sz | 89 | 2 |
| sz | 78 | 3 |
| sz | 76 | 4 |
| sz | 50 | 5 |
10 rows in set (0.00 sec)
5.分組後並列排名:組內相同數值排名相同
mysql> select city,score,rank
-> from
-> select *,
-> if(@p=city,
-> case
-> when @s=score then @r
-> when @s:=score then @r:=@r+1
-> end,
-> @r:=1 ) as rank,
-> @p:=city,
-> @s:=score
-> from tb_rank_score,(select @p:=null,@s:=null,@r:=0)r
-> order by city,score desc
-> )s;
| city | score | rank |
| sh | 90 | 1 |
| sh | 78 | 2 |
| sh | 76 | 3 |
| sh | 67 | 4 |
| sh | 34 | 5 |
| sz | 89 | 1 |
| sz | 89 | 1 |
| sz | 78 | 2 |
| sz | 76 | 3 |
| sz | 50 | 4 |
10 rows in set (0.00 sec)
6.分組後取各組的前三名
mysql> select city,score,rank
-> from
-> select *,
-> if(@p=city,
-> case
-> when @s=score then @r
-> when @s:=score then @r:=@r+1
-> end,
-> @r:=1 ) as rank,
-> @p:=city,
-> @s:=score
-> from tb_rank_score,(select @p:=null,@s:=null,@r:=0)r
-> order by city,score desc
-> )s
-> where rank <4;
| city | score | rank |
| sh | 90 | 1 |
| sh | 78 | 2 |
| sh | 76 | 3 |
| sz | 89 | 1 |
| sz | 89 | 1 |
| sz | 78 | 2 |
| sz | 76 | 3 |
7 rows in set (0.00 sec)
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