這是原始數據,并希望根據得分(count(tbl_1.id))對它們進行排名.

[tbl_1]

===========

id | name

===========

1 | peter

2 | jane

1 | peter

2 | jane

3 | harry

3 | harry

3 | harry

3 | harry

4 | ron

因此,制作臨時表(tbl_2)來計算每個id的分數.

SELECT id, name, COUNT( id ) AS score

FROM tbl_1

GROUP BY id

ORDER BY score DESC;

LIMIT 0, 30;

然后結果是;

[tbl_2]

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

id | name | score

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

3 | harry | 4

1 | peter | 2

2 | jane | 2

4 | ron | 1

然后查詢這個;

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;

然后結果是;

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

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個事務(查詢)中執行此操作？

最佳答案 是的,可以在單個查詢中執行此操作.但它在MySQL中是一個完整的毛球,因為MySQL沒有簡單的ROWNUM操作,你需要一個用于排名計算.

這是您顯示排名的投票查詢. @ranka變量用于對行進行編號.

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

正如您已經發現的那樣,您需要自行加入此項以獲得正確的排名(正確處理關系).因此,如果您接受查詢并將兩個引用替換為您的投票表,每個引用都有自己的子查詢版本,那么您將獲得所需的內容.

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;

告訴你這是一個毛球.請注意,在您自行加入的子查詢的兩個版本中需要不同的@ranka和@rankb變量,以使行編號正常工作：這些變量在MySQL中具有連接范圍,而不是子查詢范圍.

編輯：使用PostgreSQL的RANK()函數更容易做到這一點.

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

FROM (

SELECT name, count(id) votes

FROM tab

GROUP BY name

)x

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