[英]Conditional count when case = 1, DB2
我目前正在尝试找出在 Iseries 的 DB2 中将条件计数作为别名的最佳方法。 以下值表示可以创建、完成和取消作业的作业状态,因此任何一项作业都可能附加多个状态代码。
但是,对于我的最终价值,我正在尝试计算仅具有已创建状态的工作,以便我可以显示仍有多少工作处于开放状态。 基本上寻找已创建案例的计数 = 1,但以下在“=”处失败的案例
SELECT
COUNT(CASE A1.JOB WHEN = 'CREATED' THEN 1 END) AS CREATED,
COUNT(CASE A1.JOB WHEN = 'CANCELLED' THEN 1 END) AS CANCELLED,
COUNT(CASE WHEN A1.JOB 'CREATED' = 1 then 1 END) AS OPEN
FROM SCHEMA.TABLE A1;
样本数据和结果:
Job ID | Status_code
-------------------------
123 'CREATED'
123 'COMPLETED'
521 'CREATED'
521 'CANCELLED'
645 'CREATED'
结果:
JOB | CREATED | CANCELLED | OPEN
-------------------------------------------
123 1 0 0
521 1 1 0
645 1 0 1
假设唯一的“关闭”状态是'CANCELLED'
,您可以像这样使用not exists
:
select count(*)
from schema.table t
where t.status_code = 'CREATED' and
not exists (select 1
from schema.table t2
where t2.job = t.job and
t2.status_code in ('CANCELLED', 'COMPLETED', 'DELETED')
);
如果您想要多个计数,那么像这样的过滤不起作用。 所以先按工作汇总:
select sum(is_created) as num_created,
sum(is_cancelled) as num_cancelled,
sum(is_created * (1 - is_cancelled) * (1 - is_completed) * (1 - is_deleted)) as open
from (select job,
max(case when status_code = 'CREATED' then 1 else 0 end) as is_created,
max(case when status_code = 'CANCELLED' then 1 else 0 end) as is_cancelled,
max(case when status_code = 'COMPLETED' then 1 else 0 end) as is_completed,
max(case when status_code = 'DELETED' then 1 else 0 end) as is_deleted
from t
group by job
) j
使用条件聚合:
SELECT
JobID,
MAX(CASE Status_code WHEN 'CREATED' THEN 1 ELSE 0 END) AS CREATED,
MAX(CASE Status_code WHEN 'CANCELLED' THEN 1 ELSE 0 END) AS CANCELLED,
MIN(CASE WHEN Status_code <> 'CREATED' THEN 0 ELSE 1 END) AS OPEN
FROM tablename
GROUP BY JobID
请参阅演示。
结果:
> JobID | CREATED | CANCELLED | OPEN
> ----: | ------: | --------: | ---:
> 123 | 1 | 0 | 0
> 521 | 1 | 1 | 0
> 645 | 1 | 0 | 1
以下返回您需要的结果:
WITH TAB (Job_ID, JOB) AS
(
VALUES
(123, 'CREATED')
, (123, 'COMPLETED')
, (521, 'CREATED')
, (521, 'CANCELLED')
, (645, 'CREATED')
)
SELECT
Job_ID
, COUNT(CASE A1.JOB WHEN 'CREATED' THEN 1 END) AS CREATED
, COUNT(CASE A1.JOB WHEN 'CANCELLED' THEN 1 END) AS CANCELLED
, CASE
WHEN NULLIF(COUNT(1), 0) = COUNT(CASE A1.JOB WHEN 'CREATED' then 1 END)
THEN 1
ELSE 0
END AS OPEN
FROM TAB A1
GROUP BY JOB_ID;
假设有效的关闭状态是“COMPLETED”或“CANCELLED”,您可以尝试关注 SQL。
SELECT
A1.JobID,
sum(CASE WHEN A1.Status_code = 'CREATED' THEN 1 ELSE 0 END) AS CREATED,
sum(CASE WHEN A1.Status_code = 'CANCELLED' THEN 1 ELSE 0 END) AS CANCELLED,
(
SUM(CASE WHEN A1.Status_code = 'CREATED' THEN 1 ELSE 0 END)
- sum(CASE WHEN A1.Status_code = 'CANCELLED' THEN 1 ELSE 0 END)
- sum(CASE WHEN A1.Status_code = 'COMPLETED' THEN 1 ELSE 0 END)
) AS OPEN
FROM SCHEMA.TABLE A1
GROUP BY A1.JobID
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