"TRUNCATE" 处或附近的语法错误 - Aurora Postgres 10.12

Question

我正在尝试重构查询并删除一组 window 函数，而不是按原样捕获所有记录。当我去粘贴查询来替换我的函数时，pgAdmin 在 'Truncate' 语句附近指示语法错误。我只是无法弄清楚它是什么，并且可能是非常明显的东西，但会欣赏另一组（或许多）眼睛。

我正在使用 Postgres 10.12。

这是我要插入的代码（最后包含 'before' 代码。任何建议将不胜感激。尝试了括号、逗号和半-的所有类型和组合结肠关闭和无能为力...

我要插入的代码

预期结果： 从分段中取出行并插入到目标中。 T运行完成后分期

  WITH ins_agent AS (
     INSERT INTO agents (
        currentagentsnapshot,
        previousagentsnapshot,
        agentarn,
        eventid,
        eventtimestamp,
        eventtype,
        instancearn)
     SELECT 
        agent_stg.currentagentsnapshot::jsonb AS currentagentsnapshot,
        agent_stg.previousagentsnapshot::jsonb AS previousagentsnapshot,
        agent_stg.agentarn::text AS agentarn,
        agent_stg.eventid::text AS eventid,
        agent_stg.eventtimestamp::timestamptz AS eventtimestamp,
        agent_stg.eventtype::text AS eventtype,
        agent_stg.instancearn::text AS instancearn
    FROM agents_staging AS agent_stg
    WHERE agent_stg.agentarn IS NOT NULL)
    TRUNCATE agents_staging;

我正在尝试更改的代码

预期结果：Select 不同的代理并捕获他们的最新快照。将 agent_id 插入另一个 table。考虑更新。

更改原因： 除了作为对数百万条记录的运行查询的负担之外，它提供的价值很小，因为它丢弃了所有代理快照，除了它们的最新的，因为不同。不是我们想要的。

WITH ins_agent AS (INSERT INTO agents (currentagentsnapshot,
                                       previousagentsnapshot,
                                       agentarn,
                                       eventid,
                                       eventtimestamp,
                                       eventtype,
                                       instancearn)
    SELECT DISTINCT LAST_VALUE(currentagentsnapshot::jsonb)
                    OVER (PARTITION BY agentarn ORDER BY lat.eventtimestamp DESC ) AS previousagentsnapshot,
                    LAST_VALUE(previousagentsnapshot::jsonb)
                    OVER (PARTITION BY agentarn ORDER BY lat.eventtimestamp DESC ) AS previousagentsnapshot,
                    agentarn,
                    LAST_VALUE(eventid)
                    OVER (PARTITION BY agentarn ORDER BY lat.eventtimestamp DESC)  AS eventid,
                    LAST_VALUE(lat.eventtimestamp)
                    OVER (PARTITION BY agentarn ORDER BY lat.eventtimestamp DESC)  AS eventtimestamp,
                    LAST_VALUE(eventtype)
                    OVER (PARTITION BY agentarn ORDER BY lat.eventtimestamp DESC)  AS eventtype,
                    LAST_VALUE(instancearn)
                    OVER (PARTITION BY agentarn ORDER BY lat.eventtimestamp DESC)  AS instancearn
    FROM agents_staging AS agent
             CROSS JOIN LATERAL (SELECT agent.eventtimestamp::timestamp AS eventtimestamp) AS lat
    WHERE NOT (
            agent.agentarn IS NULL
            OR agent.currentagentsnapshot IS NULL
            OR agent.currentagentsnapshot = '{}')
    ON CONFLICT (agentarn)
        DO NOTHING
    RETURNING agentarn, agent_id)
UPDATE contact_trace_records
SET agent_id=ins_agent.agent_id
FROM ins_agent
WHERE contact_trace_records.agent_id IS NULL
  AND ins_agent.agentarn = contact_trace_records.agent ->> 'ARN';

TRUNCATE agents_staging;

Answer 1

语法错误是无法将 CTE 附加到 TRUNCATE 命令。仅限 INSERT、UPDATE、DELETE 或 SELECT。（好吧，技术上也是 TABLE，但这只是 SELECT * FROM 的简短语法。）

删除 WITH 子句和运行两个单独的命令。

INSERT INTO agents (
    currentagentsnapshot,
    previousagentsnapshot,
    agentarn,
    eventid,
    eventtimestamp,
    eventtype,
    instancearn)
SELECT 
    agent_stg.currentagentsnapshot::jsonb AS currentagentsnapshot,
    agent_stg.previousagentsnapshot::jsonb AS previousagentsnapshot,
    agent_stg.agentarn::text AS agentarn,
    agent_stg.eventid::text AS eventid,
    agent_stg.eventtimestamp::timestamptz AS eventtimestamp,
    agent_stg.eventtype::text AS eventtype,
    agent_stg.instancearn::text AS instancearn
FROM agents_staging AS agent_stg
WHERE agent_stg.agentarn IS NOT NULL;

TRUNCATE agents_staging;

如果你需要防止竞争条件，将整个操作包装在一个事务中并首先在 table 上获取写锁：

BEGIN;
LOCK TABLE agents_staging;
INSERT ...;
TRUNCATE agents_staging;
COMMIT;

旁白：table 外 SELECT 中的别名在 INSERT 命令中 什么都不做 。这些充其量只是文档。但是由于所有列都已经有了最终的名称，所以它实际上只是噪音。

如果源列具有兼容的数据类型（隐式或赋值转换为目标类型，而不是显式转换），您可能不需要 table 限定或显式转换。看起来两个 table 都具有相同的数据类型？然后你可以在很大程度上简化为：

INSERT INTO agents
      (currentagentsnapshot, previousagentsnapshot, agentarn, eventid, eventtimestamp, eventtype, instancearn)
SELECT currentagentsnapshot, previousagentsnapshot, agentarn, eventid, eventtimestamp, eventtype, instancearn
FROM   agents_staging
WHERE  agentarn IS NOT NULL;

"TRUNCATE" 处或附近的语法错误 - Aurora Postgres 10.12

Syntax error at or near "TRUNCATE" - Aurora Postgres 10.12

sql

postgresql

common-table-expression

aws-aurora-serverless

sql-truncate