我一直在制作一款基于Candy Crush的游戏。 Score表有以下三列:
stage_level_id | value | moves
------------------------------------------------------
9f7678f0-fc8f-11e3-a398-b2227cce2b53 | 35000 | 350
9f7678f0-fc8f-11e3-a398-b2227cce2b53 | 35000 | 500
9f7678f0-fc8f-11e3-a398-b2227cce2b54 | 15000 | 125
9f7678f0-fc8f-11e3-a398-b2227cce2b54 | 13500 | 100
9f7678f0-fc8f-11e3-a398-b2227cce2b55 | 12500 | 350
9f7678f0-fc8f-11e3-a398-b2227cce2b55 | 7500 | 25
我需要得到stage_level_id
分组的最高分。如果stage_level_id
具有相同的Value
(以53结尾的那个),它必须返回具有最小数量的Moves
的行。
我正在尝试以下但它没有按预期工作:
SELECT a.stage_level_id, MAX(a.value) as max_value, a.moves
FROM scores a
LEFT JOIN scores b ON (
a.stage_level_id = b.stage_level_id
)
RIGHT JOIN scores c ON (
c.moves = ( SELECT MIN(moves) as moves FROM scores WHERE c.stage_level_id = a.stage_level_id )
)
WHERE a.player_id = 1475332386040815
GROUP BY a.stage_level_id
预期的结果是:
stage_level_id | value | moves
------------------------------------------------------
9f7678f0-fc8f-11e3-a398-b2227cce2b53 | 35000 | 350
9f7678f0-fc8f-11e3-a398-b2227cce2b54 | 15000 | 125
9f7678f0-fc8f-11e3-a398-b2227cce2b55 | 12500 | 350
我做错了什么?
你的尝试并没有那么遥远。您错过了第一个JOIN ... ON子句的必要部分,但第二个JOIN不是必需的。
SELECT tbl1.stage_level_id, tbl1.max_value, MIN(s.moves) AS moves
FROM
(
SELECT stage_level_id, MAX(value) AS max_value
FROM scores
GROUP BY stage_level_id
) tbl1
LEFT JOIN scores s ON tbl1.stage_level_id = s.stage_level_id AND tbl1.max_value = s.value
GROUP BY stage_level_id
您可以使用NOT EXISTS
获取每个(stage_id,max score)组的最小移动次数
select stage_level_id, max(value), min(moves)
from scores s1
where not exists (
select 1 from scores s2
where s2.stage_level_id = s1.stage_level_id
and s2.value > s1.value
)
group by stage_level_id;
not exists
部分将结果限制为仅在每个组中具有最高分数的行(换句话说,不存在组内具有更高分数的其他行)。
此查询可以利用(stage_id,value)
上的复合索引
不确定我是否误解了这个问题,但不是这么简单:
SELECT column1, max(column2), IF(column1 like "%53", min(column3), max(column3))
FROM test
GROUP BY column1
;
看看这个,SQLFiddle link
事实上,这可以通过一个select
与left join
和group by
简单地完成:
select s1.stage_level_id, s1.score, min(s1.moves) as moves
from scores s1
left join scores s2
on s2.stage_level_id = s1.stage_level_id
and s2.score > s1.score
where s2.score IS NULL
group by s1.stage_level_id;
left join
给出:
| s1 | s2 |
|--------------------------------------|-------|-------|--------------------------------------|--------|--------|
| stage_level_id | score | moves | stage_level_id | score | moves |
| 9f7678f0-fc8f-11e3-a398-b2227cce2b53 | 35000 | 350 | (null) | (null) | (null) |
| 9f7678f0-fc8f-11e3-a398-b2227cce2b53 | 35000 | 500 | (null) | (null) | (null) |
| 9f7678f0-fc8f-11e3-a398-b2227cce2b54 | 15000 | 125 | (null) | (null) | (null) |
| 9f7678f0-fc8f-11e3-a398-b2227cce2b54 | 13500 | 100 | 9f7678f0-fc8f-11e3-a398-b2227cce2b54 | 15000 | 125 |
| 9f7678f0-fc8f-11e3-a398-b2227cce2b55 | 7500 | 25 | 9f7678f0-fc8f-11e3-a398-b2227cce2b55 | 12500 | 350 |
| 9f7678f0-fc8f-11e3-a398-b2227cce2b55 | 12500 | 350 | (null) | (null) | (null) |
where
子句选择每个stage_level_id
包含最高分数的行:
| s1 | s2 |
|--------------------------------------|-------|-------|----------------|--------|--------|
| stage_level_id | score | moves | stage_level_id | score | moves |
| 9f7678f0-fc8f-11e3-a398-b2227cce2b53 | 35000 | 350 | (null) | (null) | (null) |
| 9f7678f0-fc8f-11e3-a398-b2227cce2b53 | 35000 | 500 | (null) | (null) | (null) |
| 9f7678f0-fc8f-11e3-a398-b2227cce2b54 | 15000 | 125 | (null) | (null) | (null) |
| 9f7678f0-fc8f-11e3-a398-b2227cce2b55 | 12500 | 350 | (null) | (null) | (null) |
这样我们就可以在min(s1.moves)
制定的每个stage_level_id
组上运行group by
来获得最终结果:
| s1 | s2 |
|--------------------------------------|-------|-------|----------------|--------|--------|
| stage_level_id | score | moves | stage_level_id | score | moves |
| 9f7678f0-fc8f-11e3-a398-b2227cce2b53 | 35000 | 350 | (null) | (null) | (null) |
| 9f7678f0-fc8f-11e3-a398-b2227cce2b54 | 15000 | 125 | (null) | (null) | (null) |
| 9f7678f0-fc8f-11e3-a398-b2227cce2b55 | 12500 | 350 | (null) | (null) | (null) |
要么
| stage_level_id | score | moves |
|--------------------------------------|-------|-------|
| 9f7678f0-fc8f-11e3-a398-b2227cce2b53 | 35000 | 350 |
| 9f7678f0-fc8f-11e3-a398-b2227cce2b54 | 15000 | 125 |
| 9f7678f0-fc8f-11e3-a398-b2227cce2b55 | 12500 | 350 |