Question

我有以下SQL脚本，它在排行榜表中对一组用户进行排名。

UPDATE leaderboard
JOIN   (SELECT f.winnings ,
IF     (@lastPoint <> f.winnings,
        @curRank := @curRank +1, 
        @curRank) AS rank, 
        @lastPoint := f.winnings
FROM   leaderboard f
JOIN   (SELECT @curRank := 0, @lastPoint := 0) r
WHERE f.competition =5
ORDER BY f.winnings DESC
) ranks ON (ranks.winnings = leaderboard.winnings)
SET leaderboard.rank = ranks.rank WHERE leaderboard.id =89;

然而，当所有用户的等级为0时，它不会将它们排在1（即相等），这种行为只发生在0。

winnings  rank
0          0
0          0
0          0

有谁知道怎么做...？

winnings  rank
0          1
0          1
0          1

SQL FIDDLE http://sqlfiddle.com/#!2/53c3a/1

Answer 1

只需将@LastPoint设置为无效值：

UPDATE leaderboard
JOIN   (SELECT f.winnings ,
IF     (@lastPoint <> f.winnings,
        @curRank := @curRank +1, 
        @curRank) AS rank, 
        @lastPoint := f.winnings
FROM   leaderboard f
JOIN   (SELECT @curRank := 0, @lastPoint := -1) r
ORDER BY f.winnings DESC
) ranks ON (ranks.winnings = leaderboard.winnings)
SET leaderboard.rank = ranks.rank;

Answer 2

<>测试失败

UPDATE leaderboard
JOIN   (SELECT f.winnings ,
IF     (@lastPoint <> f.winnings,
        @curRank := @curRank +1, 
        @curRank) AS rank, 
        @lastPoint := f.winnings
FROM   leaderboard f
JOIN   (SELECT @curRank :=0, @lastPoint :=-1) r
ORDER BY f.winnings DESC
) ranks ON (ranks.winnings = leaderboard.winnings)
SET leaderboard.rank = ranks.rank;

MySQL排名计算，所有条目均为0

2 个答案: