Question

我有一个存储过程，用于将订单导入调查软件的数据库。目前，它导入了前一天的所有订单，但最近业务计划的变更要求每小时发送一次这些调查。导入来自不同数据库中的视图。属性1是订单号，每次调查都是唯一的，因此我们可以使用它来限制导入。

如何将其更改为不重复？

BEGIN
    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.
    SET NOCOUNT ON;

Insert INTO SurveyTable
(SurveyTable.firstname,
SurveyTable.token,
SurveyTable.email,
SurveyTable.emailstatus, 
SurveyTable.language, 
SurveyTable.remindersent, 
SurveyTable.attribute_1,
SurveyTable.attribute_2)


select 
    location,
    cast( '' as xml ).value('xs:base64Binary(sql:column( "token" ) )', 'nvarchar(MAX)' ),
    email,
    emailstatus, 
    [language],
    remindersent,
    attribute_1,
    attribute_2
from 
    (
        select 
            RTRIM([Closed_Orders_For_Survey].[Location]) location,
            crypt_gen_random(12) as token, 
            [Closed_Orders_For_Survey].[Email] email,
            'OK' emailstatus,
            'en' [language], 
            'N' remindersent, 
           [Closed_Orders_For_Survey].[Order Number] attribute_1, 
            CONVERT(VARCHAR(10), [Closed_Orders_For_Survey].[Invoice Date],110) attribute_2 
        from 
            [Closed_Orders_For_Survey]
        where 
            [Closed_Orders_For_Survey].[Order Date] >= dateadd(DAY, -1, Convert(date, GETDATE()))
    ) as x
END

P.S。令牌是用于创建调查URL的生成的唯一字符串。我们决定不使用订单号作为令牌，因为这样做太可预测，并且人们可以更改其网址以填写其他用户调查。

Answer 1

这对于非常大的数据集来说并不是最佳选择（您希望确保在attribute_1上拥有良好的索引），但是您可以执行“不存在的数据集”＃39;从已经插入的内部查询中过滤掉任何订单的子句：

select 
    location,
    cast( '' as xml ).value('xs:base64Binary(sql:column( "token" ) )', 'nvarchar(MAX)' ),
    email,
    emailstatus, 
    [language],
    remindersent,
    attribute_1,
    attribute_2
from 
    (
        select 
            RTRIM([Closed_Orders_For_Survey].[Location]) location,
            crypt_gen_random(12) as token, 
            [Closed_Orders_For_Survey].[Email] email,
            'OK' emailstatus,
            'en' [language], 
            'N' remindersent, 
           [Closed_Orders_For_Survey].[Order Number] attribute_1, 
            CONVERT(VARCHAR(10), [Closed_Orders_For_Survey].[Invoice Date],110) attribute_2 
        from 
            [Closed_Orders_For_Survey]
        where 
            [Closed_Orders_For_Survey].[Order Date] >= dateadd(DAY, -1, Convert(date, GETDATE()))
    ) as x
where 
    not exists (
        select attribute_1 
            from SurveyTable 
            where 
                attribute_1 = x.attribute_1
        )

Answer 2

这可能看起来很愚蠢，但如果令牌是主键，那么插入重复令牌的尝试将会失败。陷阱你的应用程序中的特定错误（并且强烈忽略它）并且你是金色的。

如果必须是所有一个交易，您可以随时添加＆＃34;和令牌（不从表中选择令牌）＆＃34; subselect（可能效率低下，但应该有效）。

更改where语句以排除重复项

2 个答案: