这是原始数据,并希望根据得分(count(tbl_1.id))对它们进行排名.

[tbl_1]

===========

id | name

===========

1 | peter

2 | jane

1 | peter

2 | jane

3 | harry

3 | harry

3 | harry

3 | harry

4 | ron

因此,制作临时表(tbl_2)来计算每个id的分数.

SELECT id, name, COUNT( id ) AS score

FROM tbl_1

GROUP BY id

ORDER BY score DESC;

LIMIT 0, 30;

然后结果是;

[tbl_2]

===================

id | name | score

===================

3 | harry | 4

1 | peter | 2

2 | jane | 2

4 | ron | 1

然后查询这个;

SELECT v1.id, v1.name, v1.score, COUNT( v2.score ) AS rank

FROM votes v1

JOIN votes v2 ON v1.score < v2.score

OR (

v1.score = v2.score

AND v1.id = v2.id

)

GROUP BY v1.id, v1.score

ORDER BY v1.rank ASC, v1.id ASC

LIMIT 0, 30;

然后结果是;

==========================

id | name | score | rank

==========================

3 | harry | 4 | 1

1 | peter | 2 | 2

2 | jane | 2 | 2

4 | ron | 1 | 4

是否可以很好地在一个事务(查询)中执行此操作？

最佳答案 是的,可以在单个查询中执行此操作.但它在MySQL中是一个完整的毛球,因为MySQL没有简单的ROWNUM操作,你需要一个用于排名计算.

这是您显示排名的投票查询. @ranka变量用于对行进行编号.

SELECT @ranka:=@ranka+1 AS rank, id, name, score

FROM

(

SELECT id,

name,

COUNT( id ) AS score

FROM tbl_1

GROUP BY id

ORDER BY score DESC, id

) votes,

(SELECT @ranka:=0) r

正如您已经发现的那样,您需要自行加入此项以获得正确的排名(正确处理关系).因此,如果您接受查询并将两个引用替换为您的投票表,每个引用都有自己的子查询版本,那么您将获得所需的内容.

SELECT v1.id,

v1.name,

v1.score,

COUNT( v2.score ) AS rank

FROM (

SELECT @ranka:=@ranka+1 AS rank,

id,

name,

score

FROM

(

SELECT id,

name,

COUNT( id ) AS score

FROM tbl_1

GROUP BY id

ORDER BY score DESC, name

) votes,

(SELECT @ranka:=0) r) v1

JOIN (

SELECT @rankb:=@rankb+1 AS rank,

id,

name,

score

FROM

(

SELECT id,

name,

COUNT( id ) AS score

FROM tbl_1

GROUP BY id

ORDER BY score DESC, name

) votes,

(SELECT @rankb:=0) r) v2

ON (v1.score < v2.score) OR

(v1.score = v2.score AND v1.id = v2.id)

GROUP BY v1.id, v1.score

ORDER BY v1.rank ASC, v1.id ASC

LIMIT 0, 30;

告诉你这是一个毛球.请注意,在您自行加入的子查询的两个版本中需要不同的@ranka和@rankb变量,以使行编号正常工作：这些变量在MySQL中具有连接范围,而不是子查询范围.

编辑：使用PostgreSQL的RANK()函数更容易做到这一点.

SELECT name, votes, rank() over (ORDER BY votes)

FROM (

SELECT name, count(id) votes

FROM tab

GROUP BY name

)x