Question

我有一个如下所示的MySQL表：

我想找到一个对表进行分组的查询，如下所示：

详细信息：

a_id =地图上的分隔区域

is_flag = 1-如果传感器在区域内/ 0-如果传感器不在区域内

基本上，第一张表描述了每个时间戳我的传感器在哪个区域。

第二张表告诉我传感器停留在每个区域内的时间。

我对每个area_id使用以下查询，并带有union all，以便在单个表中输出传感器在区域之间的移动时间以及每个区域内/下的停留时间。

select t.a_id, min(t.timestamp) starttime,max(t.timestamp) endtime, 
t.is_flag from(SELECT *,
ROW_NUMBER() OVER(ORDER BY a.timestamp) - ROW_NUMBER() OVER(PARTITION BY 
a.is_flag ORDER BY a.timestamp) as GRP
FROM tablename a where areas_id=25 ) t
group by is_flag , GRP, a_id

这是我的dbfiddle：https://www.db-fiddle.com/f/5pHiYKyx4yHoirRbGX4kP4/0

我的查询可以满足我的需求，但需要花费一整天的时间。

Answer 1

WITH 
cte1 AS (SELECT CAST(JSON_UNQUOTE(`timestamp`) AS DATETIME) ts,
                areas_id,
                is_in_or_out
         FROM inouts),
cte2 AS (SELECT ts,
                areas_id,
                is_in_or_out,
                CAST(ROW_NUMBER() OVER (PARTITION BY areas_id ORDER BY ts ASC) AS SIGNED)
               -CAST(ROW_NUMBER() OVER (PARTITION BY areas_id ORDER BY is_in_or_out, ts ASC) AS SIGNED) AS grp
         FROM cte1)
SELECT areas_id, 
       ANY_VALUE(is_in_or_out) is_in_or_out,
       MIN(ts) min_ts,
       MAX(ts) max_ts
FROM cte2 
GROUP BY areas_id, 
         grp
ORDER BY areas_id, min_ts;

fiddle

PS1。源数据略有更改。

PS2。 MySQL中需要CAST，因为ROW_NUMBER()会产生未签名的bigint。可以替换为0.0 + ...。

Answer 2

这是sql server的语法，但在主要dbms中应该相同

with
x as (
    -- find start/end of each period
    select areas_id, is_in_or_out is_flag, timestamp t1
    , ISNULL(ABS(is_in_or_out - LAG(is_in_or_out, 1) over (partition by areas_id order by timestamp)), 1) T_START
    , ISNULL(ABS(is_in_or_out - LEAD(is_in_or_out, 1) over (partition by areas_id order by timestamp)), 1) T_END
    from inouts
),
y as (
    select *, LEAD(t1, 1) over (partition by areas_id order by t1) t2
    from x
    WHERE T_START<>0 OR T_END<>0
)
select areas_id, is_flag, t1 starttime, t2 endtime
from y
WHERE T_START<>0 
order by areas_id, t1

应该做到这一点

Answer 3

更多信息（例如示例数据和失败的查询）将有所帮助，但看来您可以将其分组。

select a_id, is_flag, min(timestamp) as starttime, max(timestamp) as endtime
  from tablename
  group by a_id, is_flag

Answer 4

我在这里想念什么？您是否可能“思想过度”？下面的SQL提供与示例db-fiddle相同的结果集（我在副本上进行了测试），非常简单，并且运行速度更快。它为每个areas_id / is_in_or_out组合（按GROUP BY）给出一行。我不太明白为什么您需要UNION和ROW_NUMBER（）OVER来使查询复杂化。希望这可以帮助。自己尝试一下，让我知道是否有任何问题！

SELECT areas_id,
       starttime,
       endtime,
       is_in_or_out
FROM   (SELECT areas_id,
               MIN(timestamp) starttime,
               MAX(timestamp) endtime,
               is_in_or_out
        FROM   inouts
        GROUP  BY is_in_or_out,
                  areas_id) x
ORDER  BY starttime;

P.S。我认为MBeale的解决方案实际上也是正确的（尽管它错过了ORDER BY）。

通过联合查询优化分组

4 个答案: