SQL 逻辑检查是否有任何相关客户失败答案

【问题标题】：SQL logic to fail a check if any of the related customers has failedSQL 逻辑检查是否有任何相关客户失败
【发布时间】：2021-09-19 15:58:13
【问题描述】：

只有当所有相关客户也都通过检查时，我才有要求标记客户 Y。下面是两张表：

关系表：

customer_id related_customer
1 1
1 2
1 3
2 1
2 2
2 3
3 1
3 2
3 3
11 11
11 22
22 11
22 22

检查表

customer_id check_flag
1 y
2 y
3 n
11 y
22 y

我想要如下输出：

customer_id  paas_fail_flag
1 n
2 n
3 n
11 y
22 y

输出理由：因为 1,2,3 是相关客户，并且由于其中一个 (3) 在表 2 中有 n，所以所有相关客户也应该有 n。 11,22 是相关客户，并且在表 2 中都有 y。所以在输出中都应该有 y。

【问题讨论】：

标签： sql oracle join count teradata

【解决方案1】：

您需要将relationship 加入check 并使用条件聚合：

SELECT r.customer_id,
       COALESCE(MAX(CASE WHEN c.check_flag = 'n' THEN c.check_flag END), 'y') paas_fail_flag  
FROM relationship r INNER JOIN "check" c 
ON c.customer_id = r.related_customer
GROUP BY r.customer_id
ORDER BY r.customer_id

请参阅demo。

【讨论】：

谢谢，我想知道条件聚合什么时候在c2上，为什么我们要加入两次
@TrishanJaiswal 我猜你是对的。我编辑了。但是您应该知道，这只有在relationship 每个客户至少有 1 行时才有效。如果客户没有关系，那么您需要加入 2 份支票。

【解决方案2】：

这样的？第 1 - 40 行中的样本数据；查询从第 41 行开始：

SQL> WITH
  2     -- sample data
  3     rel (customer_id, related_customer)
  4     AS
  5        (SELECT 1, 1 FROM DUAL
  6         UNION ALL
  7         SELECT 1, 2 FROM DUAL
  8         UNION ALL
  9         SELECT 1, 3 FROM DUAL
 10         UNION ALL
 11         SELECT 2, 1 FROM DUAL
 12         UNION ALL
 13         SELECT 2, 2 FROM DUAL
 14         UNION ALL
 15         SELECT 2, 3 FROM DUAL
 16         UNION ALL
 17         SELECT 3, 1 FROM DUAL
 18         UNION ALL
 19         SELECT 3, 2 FROM DUAL
 20         UNION ALL
 21         SELECT 3, 3 FROM DUAL
 22         UNION ALL
 23         SELECT 11, 11 FROM DUAL
 24         UNION ALL
 25         SELECT 11, 22 FROM DUAL
 26         UNION ALL
 27         SELECT 22, 11 FROM DUAL
 28         UNION ALL
 29         SELECT 22, 22 FROM DUAL),
 30     chk (customer_id, check_flag)
 31     AS
 32        (SELECT 1, 'y' FROM DUAL
 33         UNION ALL
 34         SELECT 2, 'y' FROM DUAL
 35         UNION ALL
 36         SELECT 3, 'n' FROM DUAL
 37         UNION ALL
 38         SELECT 11, 'y' FROM DUAL
 39         UNION ALL
 40         SELECT 22, 'y' FROM DUAL),

 41     temp
 42     AS
 43     -- minimum CHECK_FLAG per customer and related customer
 44        (  SELECT r.customer_id, r.related_customer, MIN (c.check_flag) mcf
 45             FROM rel r JOIN chk c ON c.customer_id = r.related_customer
 46         GROUP BY r.customer_id, r.related_customer)
 47    SELECT customer_id, MIN (mcf) flag
 48      FROM temp
 49  GROUP BY customer_id
 50  ORDER BY customer_id;

CUSTOMER_ID FLAG
----------- ----
          1 n
          2 n
          3 n
         11 y
         22 y

SQL>

【讨论】：

【解决方案3】：

假设您的关系数据可能是稀疏的，例如：

CREATE TABLE relationship ( customer_id, related_customer ) AS
SELECT  2,  3 FROM DUAL UNION ALL
SELECT  3,  1 FROM DUAL UNION ALL
SELECT  3,  2 FROM DUAL UNION ALL
SELECT 11, 22 FROM DUAL;

CREATE TABLE "CHECK" ( customer_id, check_flag ) AS
SELECT  1, 'y' FROM DUAL UNION ALL
SELECT  2, 'y' FROM DUAL UNION ALL
SELECT  3, 'n' FROM DUAL UNION ALL
SELECT 11, 'y' FROM DUAL UNION ALL
SELECT 22, 'y' FROM DUAL;

（注意：以下查询也适用于您的密集数据，其中枚举了每个关系组合。）

然后你可以使用分层查询：

SELECT customer_id,
       MIN(check_flag) AS check_flag
FROM   (
  SELECT CONNECT_BY_ROOT(c.customer_id) AS customer_id,
         c.check_flag AS check_flag
  FROM   "CHECK" c
         LEFT OUTER JOIN relationship r
         ON (r.customer_id = c.customer_id)
  WHERE  CONNECT_BY_ISLEAF = 1
  CONNECT BY NOCYCLE
         (  PRIOR r.related_customer = c.customer_id
         OR PRIOR c.customer_id = r.related_customer )
  AND    PRIOR c.check_flag = 'y'
)
GROUP BY
       customer_id
ORDER BY
       customer_id

哪些输出：

CUSTOMER_ID CHECK_FLAG

1 n

2 n

3 n

11 y

22 y

CUSTOMER_ID	CHECK_FLAG
1	n
2	n
3	n
11	y
22	y

db小提琴here

【讨论】：