Question

我有一个排名系统，当我传递player_ID时，它将在我的player_id上方和下方返回2个值。但问题是如果上面或下面的玩家排名是相同的，它会返回所有值，但我需要五个值。

我的代码：

 SET @rank = 1, @seq = 1, @last = null;

select ranks.rank , ranks.id, ranks.scores from (   
SELECT *, @rank := if(@last = scores, @rank, @seq) AS rank, @seq := @seq + 1, @last := scores FROM testingleaderboard ORDER BY scores DESC) as ranks JOIN (

  -- find the rank of the user we want similarly
  SELECT @sd:=COUNT(id) rank
  FROM   testingleaderboard JOIN (
    -- our user's highest score
    SELECT MAX(scores) maxscore FROM testingleaderboard WHERE id = 46818
  ) userscore ON testingleaderboard.scores > userscore.maxscore

-- filter for only those who are within given range from our user's rank
) userrank ON ranks.rank BETWEEN  userrank.rank - 2  AND  userrank.rank + 3

-- sort the results
ORDER BY ranks.rank

INPUT：

id = 46818

收到的输出：

"rank"  "id"    "scores"

"426688"    "1032909"   "6138"
"426688"    "1094298"   "6138"
"426688"    "1081638"   "6138"
"426688"    "1016393"   "6138"
"426688"    "1016503"   "6138"
"426688"    "1020950"   "6138"
"426688"    "39479" "6138"
**"426688"  "46818" "6138"**
"426688"    "29181" "6138"
"426688"    "31458" "6138"
"426688"    "33779" "6138"
"426688"    "23640" "6138"
"426688"    "4852"  "6138"

必需的输出：

"426688"    "1020950"   "6138"
"426688"    "39479" "6138"
**"426688"  "46818" "6138"**
"426688"    "29181" "6138"
"426688"    "31458" "6138"

Answer 1

这是你想要的吗？

(select tlb.*
 from testingleaderboard tlb
 where tlb.score <= (select tlb2.score from testingleaderboard tlb2 where tlb2.id = @id)
 order by (tlb.id = @id) desc, score desc
 limit 3
) union all
(select tlb.*
 from testingleaderboard tlb
 where tlb.score > (select tlb2.score from testingleaderboard tlb2 where tlb2.id = @id)
 order by score asc
 limit 2
);

这将返回两个分数较小或相等的行，具有id的行和两个分数较大的行。在某些情况下，这可能会错过具有相同分数的行。弄清楚如何处理这种情况可能很棘手。

Answer 2

只需在查询结尾添加限制5。

query limit 5;

e.g。选择*从任何地方订购某些限制5;

通过sql查询限制结果

2 个答案: