列的时间戳类型没有时区,但表达式的类型为字符

Question

我试图在我试图在Redshift上实现SCD2时插入记录但是出错了.

目标表的DDL是

CREATE TABLE ditemp.ts_scd2_test (
    id INT
    ,md5 CHAR(32)
    ,record_id BIGINT IDENTITY
    ,from_timestamp TIMESTAMP
    ,to_timestamp TIMESTAMP
    ,file_id BIGINT
    ,party_id BIGINT
    )

这是insert语句:

INSERT
INTO ditemp.TS_SCD2_TEST(id, md5, from_timestamp, to_timestamp)

SELECT TS_SCD2_TEST_STAGING.id
    ,TS_SCD2_TEST_STAGING.md5
    ,from_timestamp
    ,to_timestamp
FROM (
    SELECT '20150901 16:34:02' AS from_timestamp
        ,CASE 
            WHEN last_record IS NULL
                THEN '20150901 16:34:02'
            ELSE '39991231 11:11:11.000'
            END AS to_timestamp
        ,CASE 
            WHEN rownum != 1
                AND atom.id IS NOT NULL
                THEN 1
            WHEN atom.id IS NULL
                THEN 1
            ELSE 0
            END AS transfer
        ,stage.*
    FROM (
        SELECT id
        FROM ditemp.TS_SCD2_TEST_STAGING
        WHERE file_id = 2
        GROUP BY id
        HAVING count(*) > 1
        ) AS scd2_count_ge_1
    INNER JOIN (
        SELECT row_number() OVER (
                PARTITION BY id ORDER BY record_id
                ) AS rownum
            ,stage.*
        FROM ditemp.TS_SCD2_TEST_STAGING AS stage
        WHERE file_id IN (2)
        ) AS stage
        ON (scd2_count_ge_1.id = stage.id)
    LEFT JOIN (
        SELECT max(rownum) AS last_record
            ,id
        FROM (
            SELECT row_number() OVER (
                    PARTITION BY id ORDER BY record_id
                    ) AS rownum
                ,stage.*
            FROM ditemp.TS_SCD2_TEST_STAGING AS stage
            )
        GROUP BY id
        ) AS last_record
        ON (
                stage.id = last_record.id
                AND stage.rownum = last_record.last_record
                )
    LEFT JOIN ditemp.TS_SCD2_TEST AS atom
        ON (
                stage.id = atom.id
                AND stage.md5 = atom.md5
                AND atom.to_timestamp > '20150901 16:34:02'
                )
    ) AS TS_SCD2_TEST_STAGING
WHERE transfer = 1

和短的事情了,我试图插入20150901 16:34:02到from_timestamp和39991231 11:11:11.000到to_timestamp.

得到

ERROR: 42804: column "from_timestamp" is of type timestamp without time zone but expression is of type character varying

任何人都可以建议如何解决这个问题？

Answer 1

Postgres没有将20150901 16:34:02(您的输入)识别为有效的时间/日期格式,因此它假定它是一个字符串.

请改用标准日期格式,最好是ISO-8601. 2015-09-01T16:34:02

SQLFiddle示例

Answer 2

万一有人在这里结束了试图插入到PostgreSQL中，timestamp或timestampz从来自一份声明常规或Java和得到同样的错误的变量（像我一样），我设法通过设置属性做stringtype对"unspecified"。根据文档：

指定绑定通过setString（）设置的PreparedStatement参数时要使用的类型。如果将stringtype设置为VARCHAR（默认值），则此类参数将作为varchar参数发送到服务器。如果将stringtype设置为unspecified，则参数将作为未类型化的值发送到服务器，并且服务器将尝试推断适当的类型。如果您有一个使用setString（）设置实际上是其他类型的参数（例如整数）的现有应用程序，并且无法更改该应用程序以使用适当的方法（例如setInt（）），则此功能很有用。

Properties props = [user : "user", password: "password", 
driver:"org.postgresql.Driver", stringtype:"unspecified"]
def sql = Sql.newInstance("url", props)

设置此属性后，您可以将时间戳记作为字符串变量插入，而不会在问题标题中引发错误。例如：

String myTimestamp= Instant.now().toString()
sql.execute("""INSERT INTO MyTable (MyTimestamp) VALUES (?)""",
[myTimestamp.toString()]

这样，postgresql可以正确推断时间戳的类型（来自字符串）。我希望这有帮助。