Question

在SQL 2005存储过程中，我需要运行包含1-M的查询。我需要只返回许多表中的一个，即最早的日期。

我看过In SQL how do I write a query to return 1 record from a 1 to many relationship?

和SQL conundrum, how to select latest date for part, but only 1 row per part (unique)

但我不确定在我的情况下什么是最好的解决方案，因为我还在使用Insert Into临时表并使用动态排序和分页。

这是我的SQL。我想要的是返回很多行的Foo，但只有我传入的起始和结束数据参数之间最早的b.CreatedDate，其中每个Foo的Bar通常大约有5行。

DECLARE      @StartDate datetime 
 DECLARE     @EndDate datetime 

INSERT INTO @Results
          SELECT distinct
                f.Name,
                 f.Price
                b.CreatedDate ,
                // loads more columns removed for brevity   
          FROM
                foo f
            join bar b on f.Id = b.fooId
               // loads more table removed for brevity 
          WHERE
                (@x is null OR f.Id = @x)
            AND (@Deal is null OR f.IsDeal = @Deal)
            AND (@StartDate is null OR sd.SailingDate >= @StartDate)
            AND (@EndDate is null OR sd.SailingDate <= @EndDate)
                  // loads more filters removed for brevity 

        declare @firstResult int, @lastResult int
        set @firstResult = ((@PageNumber-1) * @ItemsPerPage) + 1;
        set @lastResult = @firstResult + @ItemsPerPage;
        select @TotalResults = count(1) from @Results;

        WITH ResultItems AS
        (
            SELECT *, ROW_NUMBER() OVER (
                ORDER BY
                CASE    WHEN @SortBy = 'priceLow' THEN Price END ASC,
                CASE    WHEN @SortBy = 'Soonest' THEN CreatedDate END ASC,
                CASE    WHEN @SortBy = 'priceHigh' THEN Price END DESC
            ) As  RowNumber
            FROM @Results r
        )
        SELECT * from ResultItems
        WHERE RowNumber >= @firstResult AND RowNumber < @lastResult
        ORDER BY
        CASE
            WHEN @SortBy = 'priceHigh' THEN (RANK() OVER (ORDER BY Price desc))
            WHEN @SortBy = 'priceLow' THEN (RANK() OVER (ORDER BY Price))
            WHEN @SortBy = 'Soonest' THEN (RANK() OVER (ORDER BY CreatedDate )) 
        END

此查询将返回多个'b.CreatedDate'而不是我的过滤器之间最早的一个

更新所以我想看看如果我的源数据是：

Foo
___
1  , Hello
2  , There

Boo
___
1, 1,   2011-2-4
2, 1,   2011-3-6
3, 1,   2012-12-21
4, 2,   2012-11-2

结果将是

1, Hello,2011-2-4
2, There,  2012-11-2

Answer 1

我想我只是通过在我的查询顶部添加CTE来实现它

;with cteMinDate as (
    select FooId, min(CreatedDate) As CreatedDate
    from Bar            WHERE
          (@StartDate is null OR CreatedDate>= @StartDate)
          AND (@EndDate is null OR CreatedDate<= @EndDate)
        group by FooId
)

与此处SQL conundrum, how to select latest date for part, but only 1 row per part (unique)相同。这样做可以让我从主查询中删除日期查询部分，只在CTE中执行一次

SQL如何从1中选择日期 - 很多

1 个答案: