[英]get consecutive records in mysql
我的表结构如下
ID user_id win
1 1 1
2 1 1
3 1 0
4 1 1
5 2 1
6 2 0
7 2 0
8 2 1
9 1 0
10 1 1
11 1 1
12 1 1
13 1 1
14 3 1
我希望在mysql.like中为user_id = 1获得连续获胜(win = 1),对于user_id = 2(记录id = 5),它应该返回4(记录id 10,11,12,13),它应该返回1。
我可以在为每个用户重新审阅记录后在php中执行此操作,但我不知道如何使用查询到mysql来执行此操作。
使用php或mysql在性能方面也会更好。 任何帮助将不胜感激。谢谢!!!
内部查询计算每个条纹。 外部查询获得每个用户的最大值。 查询未经测试(但基于有效的查询)
set @user_id = null;
set @streak = 1;
select user_id, max(streak) from (
SELECT user_id, streak,
case when @user_id is null OR @user_id != user_id then @streak := 1 else @streak := @streak + 1 end as streak_formula,
@user_id := user_id,
@streak as streak
FROM my_table
) foo
group by user_id
不确定你是否设法让其他查询工作,但这是我的尝试, 绝对正在工作 - Sqlfiddle来证明它。
set @x=null;
set @y=0;
select sub.user_id as user_id,max(sub.streak) as streak
from
(
select
case when @x is null then @x:=user_id end,
case
when win=1 and @x=user_id then @y:=@y+1
when win=0 and @x=user_id then @y:=0
when win=1 and @x<>user_id then @y:=1
when win=0 and @x<>user_id then @y:=0
end as streak,
@x:=user_id as user_id
from your_table
) as sub
group by sub.user_id
如何让它在PHP页面上运行并进行测试以确定您获得了正确的结果,我还对该查询进行了优化:
mysql_query("set @y=0");
$query=mysql_query("select sub.user_id as user_id,max(sub.streak) as streak
from
(
select
case
when win=1 and @x=user_id then @y:=@y+1
when win=0 and @x=user_id then @y:=0
when win=1 and @x<>user_id then @y:=1
when win=0 and @x<>user_id then @y:=0
end as streak,
@x:=user_id as user_id
from your_table
) as sub
group by sub.user_id");
while($row=mysql_fetch_assoc($query)){
print_r($row);}
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