Question

我对Teradata SQL有一个特定的问题，我肯定有一个与相关子查询有关的答案......

基本上，在我工作的呼叫中心，每个座席都必须为他们所进行的每次通话制作案例（在公司CRM中），并且每个案件都与一个帐户相关联。我需要在特定日期为所有案例创建一组代理，然后在接下来的3天内获取在这些帐户上创建的下一个案例（如果有）。基本上我需要采取以下措施（注意所有案例都会被转移到同一个DB中，无论创建者或帐号是多少）：

SELECT
  CASES.CASE_ID, CASES.CREATION_TIMESTAMP, CASES.ACCOUNT_NUMBER, CASES.AGENT_ID
FROM
  CASES
WHERE CREATION_DATE = {d '2013-12-01'} AND AGENT_ID IN ('aaaaa','bbbbb','ccccc')

并以某种方式为每个帐户创建的下一个案例的案例ID和创建时间戳添加2列，如下所示：

SELECT
  INITIAL_CASES.CASE_ID, INITIAL_CASES.CREATION_TIMESTAMP,
  INITIAL_CASES.ACCOUNT_NUMBER,
  INITIAL_CASES.AGENT_ID,
  REPEAT.CASE_ID, REPEAT.CREATION_TIMESTAMP
FROM
  CASES AS INITIAL_CASES
LEFT JOIN

  (SELECT
    ACCOUNT_NUMBER, MIN(CREATION_TIMESTAMP) 
   FROM CASES 
   WHERE CREATION_TIMESTAMP > INITIAL_CASES.CREATION_TIMESTAMP 
   AND CREATION_DATE >= {d '2013-12-01'} 
   AND CREATION_DATE <= {d '2013-12-04'}) REPEAT

ON INITAL_CASES.ACCOUNT_NUMBER = REPEAT_CASES.ACCOUNT_NUMBER
WHERE AGENT_ID IN ('aaaaa','bbbbb','ccccc')

有些捕获是1）在我的代理创建他的案例之后，在同一帐户上可能没有或超过1个案例，因此我需要使用MIN（CREATION_TS）和WHERE CREATION_TS＆gt;的组合。 INITIAL_CREATION_TS但是，我的代理案例的初始结果集中的每一行都需要执行此查询，因为它们都有不同的时间戳。

Answer 1

您可能不需要自联接，似乎您只需要基于CREATION_TIMESTAMP的下一行数据（如果它在接下来的3天内）并且使用Windowed Aggregates很容易：

SELECT
  CASES.CASE_ID, CASES.CREATION_TIMESTAMP, CASES.ACCOUNT_NUMBER, CASES.AGENT_ID,
  CASE
    WHEN MIN(CREATION_DATE)
         OVER (PARTITION BY ACCOUNT_NUMBER 
               ORDER BY CREATION_TIMESTAMP
               ROWS BETWEEN 1 FOLLOWING AND 1 FOLLOWING) <= DATE '2013-12-04'
    THEN MIN(CASE_ID) 
         OVER (PARTITION BY ACCOUNT_NUMBER 
               ORDER BY CREATION_TIMESTAMP
               ROWS BETWEEN 1 FOLLOWING AND 1 FOLLOWING) AS next_CASE_ID,
  CASE
    WHEN MIN(CREATION_DATE) 
         OVER (PARTITION BY ACCOUNT_NUMBER 
               ORDER BY CREATION_TIMESTAMP
               ROWS BETWEEN 1 FOLLOWING AND 1 FOLLOWING) <= DATE '2013-12-04'
    THEN MIN(CREATION_TIMESTAMP) 
         OVER (PARTITION BY ACCOUNT_NUMBER 
               ORDER BY CREATION_TIMESTAMP
               ROWS BETWEEN 1 FOLLOWING AND 1 FOLLOWING) AS next_CREATION_TIMESTAMP
FROM
  CASES
WHERE CREATION_DATE = {d '2013-12-01'} AND AGENT_ID IN ('aaaaa','bbbbb','ccccc')

Join语句时间约束中的SQL Correlated Sub Query

1 个答案: