将 varchar 数据转换为日期时间失败

Question

将 varchar 数据转换为日期时间失败

bil*_*nkc 3 sql-server-2008 sql-server t-sql datetime

我们正在将数据从旧表（所有 varchar 字段）移动到强类型的对应提示中

作为这项工作的一部分，如果所有数据都可以正确转换为适当的类型，我们将从基础实体表中获取数据并将其转储到 Entity_New 中。否则，它将进入名为 Entity_Bad 的现有表的副本。

我们有一个规则引擎，可以在理论上验证数据和类型，因此即使数据存储在字符字段中，数据也应该是干净的。现实是我在这里发帖是因为有些事情已经过去了，我找不到了。Entity 中的 CompletionDate 字段是 varchar(46) NULL

环境是

productversion  productlevel   edition
10.0.4064.0     SP2            Enterprise Edition (64-bit)

Run Code Online (Sandbox Code Playgroud)

我的脚本展示了我在做什么以及什么在起作用但没有起作用

SET NOCOUNT ON

DECLARE
    @startid int = 0
,   @stopid int = 796833


-------------------------------------------------------------------------------
-- Check doesn't find anything wrong with CompletionDate
-------------------------------------------------------------------------------
SELECT
    1
FROM
    [dbo].[Entity] E
    INNER JOIN
        dbo.EntityBatch_New PB
        ON E.FiscalYear = PB.FiscalYear
            AND E.HashCode = PB.HashCode
            AND E.AAKey = PB.AAKey
            AND PB.ProcessResultCode IN ('A','W','M')
WHERE
    PB.EntityBatchId BETWEEN @StartId AND @StopId
    AND
    (
        -- check
        (isDate(E.[CompletionDate]) = 0 AND E.[CompletionDate] IS NOT NULL)
        AND (isDate(E.[CompletionDate]) = 1 AND CAST(E.[CompletionDate] AS datetime) BETWEEN '1753-01-01T00:00:00.000' AND '9999-12-31T23:59:59.997')
    )

-------------------------------------------------------------------------------
-- Only row that shows as non-date is the NULL one, which is expected
-------------------------------------------------------------------------------
SELECT DISTINCT
    (E.[CompletionDate] )
,  isDate(E.[CompletionDate])
FROM
    [dbo].[Entity] E
    INNER JOIN
        dbo.EntityBatch_New PB
        ON E.FiscalYear = PB.FiscalYear
            AND E.HashCode = PB.HashCode
            AND PB.ProcessResultCode IN ('A','W','M')
    -- Ensure we aren't pulling something we have already processed
    LEFT OUTER JOIN
        [dbo].[Entity_new] N
        ON N.HashCode = E.HashCode
            AND N.FiscalYear = E.FiscalYear
                AND E.AAKey = N.AAKey
    -- Ensure we aren't pulling something we have already processed (or was bad)
    LEFT OUTER JOIN
        [dbo].[Entity_bad] BAD
        ON BAD.HashCode = E.HashCode
            AND BAD.FiscalYear = E.FiscalYear
                AND E.AAKey = BAD.AAKey
WHERE
    PB.EntityBatchId BETWEEN @StartId AND @StopId
    AND N.FiscalYear IS NULL
    AND BAD.FiscalYear IS NULL
ORDER BY 2

-------------------------------------------------------------------------------
-- Make the cast and it blows with
-- The conversion of a varchar data type to a datetime data type resulted in an out-of-range value.
-------------------------------------------------------------------------------
SELECT DISTINCT
    (E.[CompletionDate] )
,   CAST(E.[CompletionDate] AS datetime) AS [CompletionDate]
FROM
    [dbo].[Entity] E
    INNER JOIN
        dbo.EntityBatch_New PB
        ON E.FiscalYear = PB.FiscalYear
            AND E.HashCode = PB.HashCode
            AND PB.ProcessResultCode IN ('A','W','M')
    -- Ensure we aren't pulling something we have already processed
    LEFT OUTER JOIN
        [dbo].[Entity_new] N
        ON N.HashCode = E.HashCode
            AND N.FiscalYear = E.FiscalYear
                AND E.AAKey = N.AAKey
    -- Ensure we aren't pulling something we have already processed (or was bad)
    LEFT OUTER JOIN
        [dbo].[Entity_bad] BAD
        ON BAD.HashCode = E.HashCode
            AND BAD.FiscalYear = E.FiscalYear
                AND E.AAKey = BAD.AAKey
WHERE
    PB.EntityBatchId BETWEEN @StartId AND @StopId
    AND N.FiscalYear IS NULL
    AND BAD.FiscalYear IS NULL


-------------------------------------------------------------------------------
-- Dump the values into a temporary table to slice and dice the values
-------------------------------------------------------------------------------
DECLARE @debug TABLE
(
    CompletionDate varchar(46) NULL
)
INSERT INTO
    @debug
SELECT DISTINCT
    (E.[CompletionDate] )
FROM
    [dbo].[Entity] E
    INNER JOIN
        dbo.EntityBatch_New PB
        ON E.FiscalYear = PB.FiscalYear
            AND E.HashCode = PB.HashCode
            AND PB.ProcessResultCode IN ('A','W','M')
    -- Ensure we aren't pulling something we have already processed
    LEFT OUTER JOIN
        [dbo].[Entity_new] N
        ON N.HashCode = E.HashCode
            AND N.FiscalYear = E.FiscalYear
                AND E.AAKey = N.AAKey
    -- Ensure we aren't pulling something we have already processed (or was bad)
    LEFT OUTER JOIN
        [dbo].[Entity_bad] BAD
        ON BAD.HashCode = E.HashCode
            AND BAD.FiscalYear = E.FiscalYear
                AND E.AAKey = BAD.AAKey
WHERE
    PB.EntityBatchId BETWEEN @StartId AND @StopId
    AND N.FiscalYear IS NULL
    AND BAD.FiscalYear IS NULL


-------------------------------------------------------------------------------
-- This is operating on all the same values as the failing query but magically works
-------------------------------------------------------------------------------
SELECT ALL
    CAST(E.[CompletionDate] AS datetime) AS [CompletionDate]
FROM
    @debug E



-------------------------------------------------------------------------------
-- Clearly, something is amiss when we extract the data so process each row
-- and find the culprit that way. Except this finds nothing wrong
-------------------------------------------------------------------------------
DECLARE @hash uniqueidentifier
,   @zee_date varchar(46)
,   @real_date datetime

DECLARE
    CSR CURSOR READ_ONLY
FOR
SELECT
    E.HashCode
,   E.[CompletionDate]
FROM
    [dbo].[Entity] E
    INNER JOIN
        dbo.EntityBatch_New PB
        ON E.FiscalYear = PB.FiscalYear
            AND E.HashCode = PB.HashCode
            AND PB.ProcessResultCode IN ('A','W','M')
    -- Ensure we aren't pulling something we have already processed
    LEFT OUTER JOIN
        [dbo].[Entity_new] N
        ON N.HashCode = E.HashCode
            AND N.FiscalYear = E.FiscalYear
                AND E.AAKey = N.AAKey
    -- Ensure we aren't pulling something we have already processed (or was bad)
    LEFT OUTER JOIN
        [dbo].[Entity_bad] BAD
        ON BAD.HashCode = E.HashCode
            AND BAD.FiscalYear = E.FiscalYear
                AND E.AAKey = BAD.AAKey
WHERE
    PB.EntityBatchId BETWEEN @StartId AND @StopId
    AND N.FiscalYear IS NULL
    AND BAD.FiscalYear IS NULL


OPEN CSR

FETCH NEXT FROM CSR INTO
    @hash, @zee_date

WHILE (@@fetch_status = 0)
BEGIN
    BEGIN TRY
        SELECT @real_date = cast(@zee_date AS datetime)
    END TRY
    BEGIN CATCH
        print 'In here'
        print @hash
        print @zee_date
        SELECT @hash, @zee_date
    END CATCH


    FETCH NEXT FROM CSR INTO
        @hash, @zee_date

END

CLOSE csr
DEALLOCATE csr

Run Code Online (Sandbox Code Playgroud)

用上面的代码墙对您进行批评后，这里是上述查询操作的 406 个唯一值。

DECLARE @REAL_DATES TABLE
(
    CompletionDate varchar(46) NULL
)

INSERT INTO
    @REAL_DATES 
SELECT
    NULL
UNION ALL SELECT '19000101'
UNION ALL SELECT '20100208'
UNION ALL SELECT '20100228'
UNION ALL SELECT '20100309'
UNION ALL SELECT '20100314'
UNION ALL SELECT '20100401'
UNION ALL SELECT '20100409'
UNION ALL SELECT '20100420'
UNION ALL SELECT '20100427'
UNION ALL SELECT '20100429'
UNION ALL SELECT '20100507'
UNION ALL SELECT '20100615'
UNION ALL SELECT '20100617'
UNION ALL SELECT '20100629'
UNION ALL SELECT '20100701'
UNION ALL SELECT '20100703'
UNION ALL SELECT '20100704'
UNION ALL SELECT '20100706'
UNION ALL SELECT '20100709'
UNION ALL SELECT '20100713'
UNION ALL SELECT '20100714'
UNION ALL SELECT '20100715'
UNION ALL SELECT '20100716'
UNION ALL SELECT '20100720'
UNION ALL SELECT '20100721'
UNION ALL SELECT '20100726'
UNION ALL SELECT '20100727'
UNION ALL SELECT '20100728'
UNION ALL SELECT '20100729'
UNION ALL SELECT '20100731'
UNION ALL SELECT '20100801'
UNION ALL SELECT '20100802'
UNION ALL SELECT '20100803'
UNION ALL SELECT '20100804'
UNION ALL SELECT '20100807'
UNION ALL SELECT '20100809'
UNION ALL SELECT '20100810'
UNION ALL SELECT '20100811'
UNION ALL SELECT '20100813'
UNION ALL SELECT '20100817'
UNION ALL SELECT '20100819'
UNION ALL SELECT '20100820'
UNION ALL SELECT '20100822'
UNION ALL SELECT '20100823'
UNION ALL SELECT '20100825'
UNION ALL SELECT '20100827'
UNION ALL SELECT '20100828'
UNION ALL SELECT '20100830'
UNION ALL SELECT '20100831'
UNION ALL SELECT '20100901'
UNION ALL SELECT '20100902'
UNION ALL SELECT '20100904'
UNION ALL SELECT '20100907'
UNION ALL SELECT '20100908'
UNION ALL SELECT '20100909'
UNION ALL SELECT '20100910'
UNION ALL SELECT '20100911'
UNION ALL SELECT '20100913'
UNION ALL SELECT '20100916'
UNION ALL SELECT '20100919'
UNION ALL SELECT '20100920'
UNION ALL SELECT '20100922'
UNION ALL SELECT '20100923'
UNION ALL SELECT '20100925'
UNION ALL SELECT '20100928'
UNION ALL SELECT '20101002'
UNION ALL SELECT '20101004'
UNION ALL SELECT '20101007'
UNION ALL SELECT '20101009'
UNION ALL SELECT '20101010'
UNION ALL SELECT '20101013'
UNION ALL SELECT '20101016'
UNION ALL SELECT '20101018'
UNION ALL SELECT '20101019'
UNION ALL SELECT '20101020'
UNION ALL SELECT '20101022'
UNION ALL SELECT '20101023'
UNION ALL SELECT '20101025'
UNION ALL SELECT '20101028'
UNION ALL SELECT '20101030'
UNION ALL SELECT '20101102'
UNION ALL SELECT '20101107'
UNION ALL SELECT '20101108'
UNION ALL SELECT '20101109'
UNION ALL SELECT '20101111'
UNION ALL SELECT '20101112'
UNION ALL SELECT '20101114'
UNION ALL SELECT '20101117'
UNION ALL SELECT '20101119'
UNION ALL SELECT '20101124'
UNION ALL SELECT '20101126'
UNION ALL SELECT '20101127'
UNION ALL SELECT '20101129'
UNION ALL SELECT '20101201'
UNION ALL SELECT '20101203'
UNION ALL SELECT '20101204'
UNION ALL SELECT '20101206'
UNION ALL SELECT '20101209'
UNION ALL SELECT '20101210'
UNION ALL SELECT '20101213'
UNION ALL SELECT '20101214'
UNION ALL SELECT '20101215'
UNION ALL SELECT '20101216'
UNION ALL SELECT '20101220'
UNION ALL SELECT '20101222'
UNION ALL SELECT '20101227'
UNION ALL SELECT '20101228'
UNION ALL SELECT '20101229'
UNION ALL SELECT '20101230'
UNION ALL SELECT '20110102'
UNION ALL SELECT '20110103'
UNION ALL SELECT '20110104'
UNION ALL SELECT '20110106'
UNION ALL SELECT '20110107'
UNION ALL SELECT '20110108'
UNION ALL SELECT '20110109'
UNION ALL SELECT '20110110'
UNION ALL SELECT '20110111'
UNION ALL SELECT '20110114'
UNION ALL SELECT '20110116'
UNION ALL SELECT '20110118'
UNION ALL SELECT '20110119'
UNION ALL SELECT '20110120'
UNION ALL SELECT '20110122'
UNION ALL SELECT '20110123'
UNION ALL SELECT '20110125'
UNION ALL SELECT '20110126'
UNION ALL SELECT '20110128'
UNION ALL SELECT '20110130'
UNION ALL SELECT '20110203'
UNION ALL SELECT '20110205'
UNION ALL SELECT '20110206'
UNION ALL SELECT '20110208'
UNION ALL SELECT '20110210'
UNION ALL SELECT '20110212'
UNION ALL SELECT '20110213'
UNION ALL SELECT '20110215'
UNION ALL SELECT '20110218'
UNION ALL SELECT '20110221'
UNION ALL SELECT '20110224'
UNION ALL SELECT '20110226'
UNION ALL SELECT '20110301'
UNION ALL SELECT '20110302'
UNION ALL SELECT '20110304'
UNION ALL SELECT '20110307'
UNION ALL SELECT '20110309'
UNION ALL SELECT '20110311'
UNION ALL SELECT '20110314'
UNION ALL SELECT '20110316'
UNION ALL SELECT '20110317'
UNION ALL SELECT '20110320'
UNION ALL SELECT '20110321'
UNION ALL SELECT '20110323'
UNION ALL SELECT '20110326'
UNION ALL SELECT '20110328'
UNION ALL SELECT '20110329'
UNION ALL SELECT '20110331'
UNION ALL SELECT '20110403'
UNION ALL SELECT '20110405'
UNION ALL SELECT '20110406'
UNION ALL SELECT '20110408'
UNION ALL SELECT '20110410'
UNION ALL SELECT '20110415'
UNION ALL SELECT '20110416'
UNION ALL SELECT '20110417'
UNION ALL SELECT '20110418'
UNION ALL SELECT '20110421'
UNION ALL SELECT '20110422'
UNION ALL SELECT '20110423'
UNION ALL SELECT '20110426'
UNION ALL SELECT '20110429'
UNION ALL SELECT '20110501'
UNION ALL SELECT '20110503'
UNION ALL SELECT '20110504'
UNION ALL SELECT '20110506'
UNION ALL SELECT '20110508'
UNION ALL SELECT '20110509'
UNION ALL SELECT '20110511'
UNION ALL SELECT '20110512'
UNION ALL SELECT '20110514'
UNION ALL SELECT '20110517'
UNION ALL SELECT '20110518'
UNION ALL SELECT '20110519'
UNION ALL SELECT '20110520'
UNION ALL SELECT '20110522'
UNION ALL SELECT '20110526'
UNION ALL SELECT '20110531'
UNION ALL SELECT '20110603'
UNION ALL SELECT '20110604'
UNION ALL SELECT '20110605'
UNION ALL SELECT '20110606'
UNION ALL SELECT '20110608'
UNION ALL SELECT '20110611'
UNION ALL SELECT '20110613'
UNION ALL SELECT '20110614'
UNION ALL SELECT '20110616'
UNION ALL SELECT '20110622'
UNION ALL SELECT '20110624'
UNION ALL SELECT '20110627'
UNION ALL SELECT '20110703'
UNION ALL SELECT '20110704'
UNION ALL SELECT '20110711'
UNION ALL SELECT '20110712'
UNION ALL SELECT '20110713'
UNION ALL SELECT '20110714'
UNION ALL SELECT '20110719'
UNION ALL SELECT '20110720'
UNION ALL SELECT '20110725'
UNION ALL SELECT '20110726'
UNION ALL SELECT '20110802'
UNION ALL SELECT '20110804'
UNION ALL SELECT '20110811'
UNION ALL SELECT '20090611'
UNION ALL SELECT '20091124'
UNION ALL SELECT '20100201'
UNION ALL SELECT '20100202'
UNION ALL SELECT '20100204'
UNION ALL SELECT '20100220'
UNION ALL SELECT '20100305'
UNION ALL SELECT '20100323'
UNION ALL SELECT '20100414'
UNION ALL SELECT '20100417'
UNION ALL SELECT '20100508'
UNION ALL SELECT '20100512'
UNION ALL SELECT '20100527'
UNION ALL SELECT '20100616'
UNION ALL SELECT '20100702'
UNION ALL SELECT '20100705'
UNION ALL SELECT '20100707'
UNION ALL SELECT '20100708'
UNION ALL SELECT '20100710'
UNION ALL SELECT '20100711'
UNION ALL SELECT '20100712'
UNION ALL SELECT '20100717'
UNION ALL SELECT '20100719'
UNION ALL SELECT '20100722'
UNION ALL SELECT '20100723'
UNION ALL SELECT '20100724'
UNION ALL SELECT '20100725'
UNION ALL SELECT '20100730'
UNION ALL SELECT '20100805'
UNION ALL SELECT '20100806'
UNION ALL SELECT '20100808'
UNION ALL SELECT '20100812'
UNION ALL SELECT '20100814'
UNION ALL SELECT '20100815'
UNION ALL SELECT '20100816'
UNION ALL SELECT '20100818'
UNION ALL SELECT '20100821'
UNION ALL SELECT '20100824'
UNION ALL SELECT '20100826'
UNION ALL SELECT '20100829'
UNION ALL SELECT '20100903'
UNION ALL SELECT '20100906'
UNION ALL SELECT '20100912'
UNION ALL SELECT '20100914'
UNION ALL SELECT '20100915'
UNION ALL SELECT '20100917'
UNION ALL SELECT '20100918'
UNION ALL SELECT '20100921'
UNION ALL SELECT '20100924'
UNION ALL SELECT '20100926'
UNION ALL SELECT '20100927'
UNION ALL SELECT '20100929'
UNION ALL SELECT '20100930'
UNION ALL SELECT '20101001'
UNION ALL SELECT '20101003'
UNION ALL SELECT '20101005'
UNION ALL SELECT '20101006'
UNION ALL SELECT '20101008'
UNION ALL SELECT '20101011'
UNION ALL SELECT '20101012'
UNION ALL SELECT '20101014'
UNION ALL SELECT '20101015'
UNION ALL SELECT '20101017'
UNION ALL SELECT '20101021'
UNION ALL SELECT '20101024'
UNION ALL SELECT '20101026'
UNION ALL SELECT '20101027'
UNION ALL SELECT '20101029'
UNION ALL SELECT '20101031'
UNION ALL SELECT '20101101'
UNION ALL SELECT '20101103'
UNION ALL SELECT '20101104'
UNION ALL SELECT '20101105'
UNION ALL SELECT '20101106'
UNION ALL SELECT '20101110'
UNION ALL SELECT '20101113'
UNION ALL SELECT '20101115'
UNION ALL SELECT '20101116'
UNION ALL SELECT '20101118'
UNION ALL SELECT '20101120'
UNION ALL SELECT '20101122'
UNION ALL SELECT '20101123'
UNION ALL SELECT '20101125'
UNION ALL SELECT '20101128'
UNION ALL SELECT '20101130'
UNION ALL SELECT '20101202'
UNION ALL SELECT '20101205'
UNION ALL SELECT '20101207'
UNION ALL SELECT '20101208'
UNION ALL SELECT '20101212'
UNION ALL SELECT '20101217'
UNION ALL SELECT '20101218'
UNION ALL SELECT '20101219'
UNION ALL SELECT '20101221'
UNION ALL SELECT '20101223'
UNION ALL SELECT '20101224'
UNION ALL SELECT '20101226'
UNION ALL SELECT '20101231'
UNION ALL SELECT '20110101'
UNION ALL SELECT '20110105'
UNION ALL SELECT '20110112'
UNION ALL SELECT '20110113'
UNION ALL SELECT '20110115'
UNION ALL SELECT '20110117'
UNION ALL SELECT '20110121'
UNION ALL SELECT '20110124'
UNION ALL SELECT '20110127'
UNION ALL SELECT '20110129'
UNION ALL SELECT '20110131'
UNION ALL SELECT '20110201'
UNION ALL SELECT '20110202'
UNION ALL SELECT '20110204'
UNION ALL SELECT '20110207'
UNION ALL SELECT '20110209'
UNION ALL SELECT '20110211'
UNION ALL SELECT '20110214'
UNION ALL SELECT '20110216'
UNION ALL SELECT '20110217'
UNION ALL SELECT '20110219'
UNION ALL SELECT '20110220'
UNION ALL SELECT '20110222'
UNION ALL SELECT '20110223'
UNION ALL SELECT '20110225'
UNION ALL SELECT '20110228'
UNION ALL SELECT '20110303'
UNION ALL SELECT '20110305'
UNION ALL SELECT '20110306'
UNION ALL SELECT '20110308'
UNION ALL SELECT '20110310'
UNION ALL SELECT '20110312'
UNION ALL SELECT '20110313'
UNION ALL SELECT '20110315'
UNION ALL SELECT '20110318'
UNION ALL SELECT '20110322'
UNION ALL SELECT '20110324'
UNION ALL SELECT '20110325'
UNION ALL SELECT '20110327'
UNION ALL SELECT '20110330'
UNION ALL SELECT '20110401'
UNION ALL SELECT '20110404'
UNION ALL SELECT '20110407'
UNION ALL SELECT '20110409'
UNION ALL SELECT '20110411'
UNION ALL SELECT '20110412'
UNION ALL SELECT '20110413'
UNION ALL SELECT '20110414'
UNION ALL SELECT '20110419'
UNION ALL SELECT '20110420'
UNION ALL SELECT '20110425'
UNION ALL SELECT '20110427'
UNION ALL SELECT '20110428'
UNION ALL SELECT '20110430'
UNION ALL SELECT '20110502'
UNION ALL SELECT '20110505'
UNION ALL SELECT '20110507'
UNION ALL SELECT '20110510'
UNION ALL SELECT '20110513'
UNION ALL SELECT '20110515'
UNION ALL SELECT '20110516'
UNION ALL SELECT '20110521'
UNION ALL SELECT '20110523'
UNION ALL SELECT '20110524'
UNION ALL SELECT '20110525'
UNION ALL SELECT '20110527'
UNION ALL SELECT '20110528'
UNION ALL SELECT '20110530'
UNION ALL SELECT '20110601'
UNION ALL SELECT '20110602'
UNION ALL SELECT '20110607'
UNION ALL SELECT '20110609'
UNION ALL SELECT '20110610'
UNION ALL SELECT '20110615'
UNION ALL SELECT '20110617'
UNION ALL SELECT '20110618'
UNION ALL SELECT '20110620'
UNION ALL SELECT '20110621'
UNION ALL SELECT '20110623'
UNION ALL SELECT '20110626'
UNION ALL SELECT '20110628'
UNION ALL SELECT '20110629'
UNION ALL SELECT '20110630'
UNION ALL SELECT '20110701'
UNION ALL SELECT '20110706'
UNION ALL SELECT '20110707'
UNION ALL SELECT '20110708'
UNION ALL SELECT '20110715'
UNION ALL SELECT '20110717'
UNION ALL SELECT '20110721'
UNION ALL SELECT '20110722'
UNION ALL SELECT '20110727'
UNION ALL SELECT '20110729'
UNION ALL SELECT '20110801'
UNION ALL SELECT '20110810'

SELECT 
    CAST(RD.CompletionDate AS datetime) AS casts_fine
FROm
    @REAL_DATES RD

Run Code Online (Sandbox Code Playgroud)

我很欣赏关于 SSIS 或其他方法的评论，但在游戏的这一点上，我们已与 TSQL 转换方法结合。如果有人能指出我遗漏了什么，我会以你的名字命名我的第一个孩子，假设你不介意把你的名字改成詹姆斯。

Answer 1

Aar*_*and 8

当你这样做时会发生什么？

DECLARE @REAL_DATES TABLE
(
    CompletionDate VARCHAR(46)
);

INSERT INTO
    @REAL_DATES
    SELECT CompletionDate
    FROM dbo.Entity;

SELECT 
    CAST(RD.CompletionDate AS datetime) AS casts_fine
    FROM @REAL_DATES RD;

Run Code Online (Sandbox Code Playgroud)

我在 twitter 上了解到的是，优化器可以在消除行之前尝试转换，因此您不能只考虑连接返回的 CompletionDate 值。

我的第一个建议是使用正确的数据类型。为什么要使用 VARCHAR(46) 来存储日期？这就是为什么您在表中有错误数据的原因以及为什么当您想要不是字符串的丰富数据时必须显式转换的原因（恕我直言，一开始就不应该是字符串）。

我的下一个建议是更正该列中的所有数据，并采取措施使其不再无效。例如，验证ISDATE(columnname) = 1.

失败的那两个，接下来我的名单上。将数据返回给客户端，让它转换为datetime或显示器或者你有什么。无论您在哪里过滤出导致问题的行，优化器都可以推动该评估，以便在淘汰坏行之前尝试转换。

最后，您可以将查询结果转储到临时表/表变量中，并在查询该中间对象时执行转换作为第二步（因为您应该确信此处的日期有效 - 实际上您可以检查首先，如果您的连接碰巧返回一些日期无效的行，则会引发错误）。

底线：（a）您无法对将在堆栈中的哪个位置进行转换尝试做出任何假设，并且（b）如果您使用了正确的数据类型，则不需要这些变通方法和技巧。

归档时间：	14 年，2 月前
查看次数：	2322 次
最近记录：	7 年，10 月前