Question

我正在PostgreSQL中的两个表之间进行连接，一个在incidentnumber（opentickets）上有一个主键约束，而另一个表没有约束，并且可能有重复的incidentnumbers（incommingtickets）。尝试过滤掉重复项时出现问题。查询，

SELECT  incommingtickets.* 
FROM incommingtickets
    LEFT JOIN opentickets
        ON incommingtickets.incidentnumber = opentickets.incidentnumber 
WHERE opentickets.incidentnumber IS NULL
      AND incommingtickets.status NOT IN ('Closed','Cancelled', '')

一直工作，直到它碰到重复，我得到违反主键消息。如果我添加一个像<，p>这样的独特子句

SELECT  DISTINCT ON (incommingtickets.incidentnumber) incommingtickets.* 
FROM incommingtickets
    LEFT JOIN opentickets
        ON incommingtickets.incidentnumber = opentickets.incidentnumber 
WHERE opentickets.incidentnumber IS NULL
      AND incommingtickets.status NOT IN ('Closed','Cancelled', '')

我收到错误，

pg_query（）：查询失败：错误：缺少表的FROM子句条目＆＃34; incommingtickets＆＃34;第30行：哪里有opentickets.incidentnumber = incommingtickets.incident ...

Answer 1

使用WHERE子句过滤掉你不想要的副本，尽管我不清楚为什么你想加入一个＆＃39;指标＆＃39;比如门票数量。

SELECT  incommingtickets.* 
FROM incommingtickets
WHERE incommingtickets.incidentnumber not in (
        select 
        distinct 
        incidentnumber 
        FROM opentickets)
AND incommingtickets.status NOT IN ('Closed','Cancelled', '')

通过这种方式，您可以在两个表之间输出重复文件。

如果您想要检查或更新opentickets表中任何故障单的故障单状态，请尝试从incommingtickets获取最大状态，如下所示：

WITH ticket_rows AS(
    SELECT
    rank() OVER (PARTITION BY ticket_id ORDER BY ticket_timestamp desc) as row_number,
    ticket_id,
    ticket_status,
    ticket_timestamp
    from incommingtickets
)

SELECT  incommingtickets.*, opentickets_2.* 
FROM opentickets o
    LEFT JOIN ticket_rows ON ticket_rows.ticket_id= opentickets.ticket_id AND ticket_rows.row__number=1

如果这些不是你的目标，那么请你更好地解释你想要通过左连接实现的目标。

PostgreSQL加入一个不同的子句

1 个答案: