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  • TSql 实现类似访问数组变量的操作

          目前T-SQL不支持Array这种类型,大多数情况我们需要用游标来实现。除了游标后我们还可以用临时表,这里我们演示使用表变量来实现,直接看下来的T-SQL:

    --Then "iterate" through it executing the necessary SQL from those values.
    --This will allow you to have 0 to MANY values to be executed, so you don't have to set up a variable for each.
    --The following is a complete sample of how you may go about doing that without cursors.
     
    SET NOCOUNT ON
    DECLARE @dict TABLE (
                        id          INT IDENTITY(1,1), -- a unique identity column for reference later
                        value       VARCHAR(50),       -- your parameter value to be passed into the procedure
                        executed    BIT                -- BIT to mark a record as being executed later
                        )
     
    -- INSERT YOUR VALUES INTO @dict HERE
    -- Set executed to 0 (so that the executio    n process will pick it up later)
    -- This may be a SELECT statement into another table in your database to load the values into @dict
    INSERT @dict
    SELECT '390adbc5-3494-4651-95af-608b69a304c1',0  UNION ALL
    SELECT 'ddf23828-fbf9-4d16-81fa-3f4b465539a3',0     UNION ALL
    SELECT '02627340-22cd-4758-807d-6251acd5a0e5',0    
         
    DECLARE @currentid INT
    DECLARE @currentvalue VARCHAR(50)
    WHILE EXISTS(SELECT * FROM @dict WHERE executed = 0)
    BEGIN
        -- Get the next record to execute
        SELECT 
        TOP 1   @currentid = id 
        FROM    @dict 
        WHERE   executed = 0
     
        -- Get the parameter value
        SELECT  @currentvalue = value
        FROM    @dict
        WHERE   id = @currentid
     
        -- EXECUTE THE SQL HERE 
        ---BEGIN
        PRINT   'SecondSP ' +  '@myParam int ' + '@myParam = ' + @currentvalue
        -- END
        
        -- Mark record as having been executed
        UPDATE  d
        SET     executed = 1
        FROM    @dict d
        WHERE   id = @currentid
     
    END

    上面的T-SQL先创建一个表变量,然后插入初始数据,这些数据可能是你需要处理的数据。然后有一个设有一个标志列标记当前行有没有执行过。你可以根据上面的代码模板修改成为你自己的。

    希望对您开发有帮助。

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    作者:Petter Liu
    出处:http://www.cnblogs.com/wintersun/
    本文版权归作者和博客园共有,欢迎转载,但未经作者同意必须保留此段声明,且在文章页面明显位置给出原文连接,否则保留追究法律责任的权利。
    该文章也同时发布在我的独立博客中-Petter Liu Blog

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  • 原文地址:https://www.cnblogs.com/wintersun/p/2550349.html
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