SQL 服务器加入子查询

Question

我有两个 SQL 表：表 A 和表 B

表A

批处理标识符（varchar）	批处理状态（位）	dt_utc（日期时间）	批处理任务
batch_id1	0	2022-09-15 10:00:00	1
batch_id1	1	2022-09-15 11:00:00	1
batch_id2	0	2022-09-15 10:30:00	4

表B

批处理标识符（varchar）	任务状态（位）	任务描述（varchar）	任务标识符（varchar）
batch_id1	0	2022-09-15 10:00:00	task_id1
batch_id1	1	2022-09-15 10:50:00	task_id1
batch_id2	0	2022-09-15 10:30:00	task_id1
batch_id2	1	2022-09-15 10:35:00	task_id1
batch_id2	0	2022-09-15 10:36:00	task_id2
batch_id2	0	2022-09-15 10:37:00	task_id3

我想要做的是以下几点：
获取“进行中”批处理表（即 batch_status = 0）以及已执行的任务。 因此，例如在上面的示例中，唯一仍在运行的批处理是 batch_id2，而相关的已完成任务是 task_id1。

到目前为止，我已经对此进行了测试但没有成功：

select
*
from
 (
    select
        batch_identifier,
        MAX(CAST(batch_status as int)) as _status
    from
        dbo.TableA
    group by
        batch_identifier
) data
where _status = 0 ??

你能帮忙吗？

batch_identifier和task_identifier是 SQL 索引。

Answer 1

也许像其中之一？

SELECT batch_identifier, db_utc, Zero, One
FROM TableA
    LEFT JOIN (
        SELECT batch_identifier,
            SUM(CASE WHEN task_status = 0 THEN 1 ELSE 0 END) AS Zero,
            SUM(CASE WHEN task_status = 1 THEN 1 ELSE 0 END) AS One
        FROM TableB
        GROUP BY batch_identifier
    ) AS b
        ON a.batch_identifier = b.batch_identifier

SELECT *
FROM TableA a
WHERE NOT EXISTS (
    SELECT NULL FROM TableB b WHERE b.batch_identifier = a.batch_identifier AND b.task_status = 0
)

Answer 2

如果我对您的理解正确，我认为您不需要子查询。

尝试：

SELECT batch_identifier, task_identifier, MAX(CAST(batch_status as int)) as _status
FROM dbo.TableA a
INNER JOIN dbo.TableB b ON a.batch_identifier = b.batch_identifier AND task_status = 1
WHERE batch_status = 0
GROUP BY batch_identifier, task_identifier

Answer 3

使用公用表表达式来获取哪些批次仍在进行中。 然后我将获取 TableB 中的详细信息，并按批次和任务标识符分组，并检查任务状态中的最大值是否为零（意味着任务仍在进行中）。

WITH data as (
    select
        batch_identifier 
    from
        dbo.TableA
    group by
        batch_identifier
    having 
        MAX(CAST(batch_status as int)) = 0)  
select
      details.batch_identifier,
      MIN(CAST(details.task_status as int)) as task_status,
      MIN(details.task_description) as task_description,
      details.task_identifier
from 
        dbo.TableB as details
inner join 
        data on data.batch_identifier = details.batch_identifier  
group by
        details.batch_identifier, 
        task_identifier
having
        MAX(CAST(details.task_status as int)) = 0

结果：

batch_identifier    task_status task_description    task_identifier 
----------------    ----------- ----------------    ------------
batch_id2           0           2022-09-15 10:36:00 task_id2
batch_id2           0           2022-09-15 10:37:00 task_id3