Question

这是我的桌子：

+--------+-------+--------+--------+
| player | points| score1 | score2 |
+--------+-------+--------+--------+
|      1 |   12  |   9    |    1   |
|      2 |   12  |   14   |    2   |
|      3 |   10  |   12   |    3   |
|      4 |   9   |   10   |    4   |
|      5 |   8   |   10   |    4   |
+--------+-------+--------+--------+

要获得第二高的值，我使用了以下查询：

SELECT player,points FROM players
WHERE points= (SELECT DISTINCT(points) FROM players as p1
WHERE (SELECT COUNT(DISTINCT(points))=2 FROM players as p2
WHERE p1.points<= p2.points)) ORDER BY player

效果很好。但是现在我想得到的是两个条件：

条件1 ：分DESC

条件2 ：（score1-score2）DESC

此查询可以很好地使玩家获得第二高的值（检查点和得分1）：

SELECT player,points FROM players

WHERE points= (SELECT DISTINCT(points) FROM players as p1
WHERE (SELECT COUNT(DISTINCT(points))=2 FROM players as p2
WHERE p1.points<= p2.points))

AND

WHERE score1= (SELECT DISTINCT(score1) FROM players as p1
WHERE (SELECT COUNT(DISTINCT(score1))=2 FROM players as p2
WHERE p1.score1<= p2.score1))

ORDER BY player

如何使用两个条件（点DESC AND（score1-score2）DESC）获得第二高的玩家？

Answer 1

此查询将执行您想要的操作。它JOIN自己players，在第二张表中寻找所有排名高于第一张表中的玩家的玩家。在这种情况下，排名首先基于points，然后在score1和score2之间的差异相等的情况下进行排名。排名第二的玩家是排名更高的玩家之一：

SELECT p1.* 
FROM players p1
JOIN players p2 ON p2.points > p1.points
                OR p2.points = p1.points AND (p2.score1 - p2.score2) > (p1.score1 - p1.score2)
GROUP BY p1.player
HAVING COUNT(p2.player) = 1

输出：

player  points  score1  score2
1       12      9       1

您还可以以类似的方式编写原始查询，使用p2.player < p1.player作为条件，用相等的分数分隔玩家（模拟ORDER BY player的效果）：

SELECT p1.* 
FROM players p1
JOIN players p2 ON p2.points > p1.points
                OR p2.points = p1.points AND p2.player < p1.player
GROUP BY p1.player
HAVING COUNT(p2.player) = 1

输出：

player  points  score1  score2
2       12      14      2

Demo on dbfiddle

在两个条件下获得第二高的值

1 个答案: