Question

这是事情：我有一张桌子 DailyContent（dailyContentId，userId，weekDayId，eventId）其中我存储了特定日期的项目（对于每个用户）。天数分为不同的事件（每天更多事件）。我想做的是选择项目（对于一个事件），但是不同的天数。天有ID从1到7.如果天被“选中”我得到dayId，否则我得到null作为输入参数。

如果选择了超过一天，则只返回所有日期共同的项目。

如果没有选择日，则不返回任何内容

我尝试过这样的事情，但我只得到一天的结果。如果我选择超过一天，则返回NOTHING（如上所述，应返回此事件的两天存储的项目。）

DECLARE @daysCount int -- only for incitation how many days are actually set
SET @daysCount = 0
IF (@mon IS NOT NULL)
    BEGIN
        SET @daysCount = @daysCount+1
    END
IF (@tue IS NOT NULL)
    BEGIN
        SET @daysCount = @daysCount+1
    END
IF (@wed IS NOT NULL)
    BEGIN
        SET @daysCount = @daysCount+1
    END
IF (@thu IS NOT NULL)
    BEGIN
        SET @daysCount = @daysCount+1
    END
IF (@fri IS NOT NULL)
    BEGIN
        SET @daysCount = @daysCount+1
    END
IF (@sat IS NOT NULL)
    BEGIN
        SET @daysCount = @daysCount+1
    END
IF (@sun IS NOT NULL)
    BEGIN
        SET @daysCount = @daysCount+1
    END

-- Insert statements for procedure here
SELECT 
    DailyContent.dailyContentId

            FROM DailyContent

    WHERE
    eventId=@eventId AND (weekDayId=@mon OR
            weekDayId=@tue OR
            weekDayId=@wed  OR
            weekDayId=@thu  OR
            weekDayId=@fri  OR
            weekDayId=@sat  OR
            weekDayId=@sun)
    GROUP BY DailyContent.dailyContentId
    HAVING (COUNT(dailyContentId) = @daysCount)

这个HAVING COUNT出了点问题。如果我删除它，它可以正常工作，但只有选择了一天。

实际上我想要的是“如果参数为空则选择所有”。

我正在使用MS SQL server 2008。

非常感谢任何帮助。

Answer 1

您是否尝试使用一个额外的if condition来处理“未选择日期”的方案。像：

IF (@daysCount<>0)
SELECT DailyContent.dailyContentId, DailyContent.itemId, title, defaultSmallImagePath
    FROM DailyContent
    LEFT OUTER JOIN
        itemsTranslations ON itemsTranslations.itemId = DailyContent.itemId
    LEFT OUTER JOIN
        itemAdditionalInformation ON itemAdditionalInformation.itemId = DailyContent.itemId
    WHERE
    eventId=@eventId AND (weekDayId=@mon OR
            weekDayId=@tue OR
            weekDayId=@wed  OR
            weekDayId=@thu  OR
            weekDayId=@fri  OR
            weekDayId=@sat  OR
            weekDayId=@sun)
    GROUP BY DailyContent.dailyContentId, DailyContent.itemId, title, defaultSmallImagePath
    HAVING (COUNT(weekDayId) = @daysCount)

Answer 2

试试这个 -

DECLARE @daysCount INT
SELECT @daysCount = 
    CASE WHEN @mon IS NOT NULL THEN 1 ELSE 0 END +
    CASE WHEN @tue IS NOT NULL THEN 1 ELSE 0 END +
    CASE WHEN @wed IS NOT NULL THEN 1 ELSE 0 END +
    CASE WHEN @thu IS NOT NULL THEN 1 ELSE 0 END +
    CASE WHEN @fri IS NOT NULL THEN 1 ELSE 0 END +
    CASE WHEN @sat IS NOT NULL THEN 1 ELSE 0 END + 
    CASE WHEN @sun IS NOT NULL THEN 1 ELSE 0 END 

SELECT dc.dailyContentId
FROM dbo.DailyContent dc
WHERE eventId = @eventId 
    AND weekDayId IN (@mon, @tue, @wed, @thu, @fri, @sat, @sun)
GROUP BY DailyContent.dailyContentId
HAVING COUNT(dailyContentId) = @daysCount

如果（可选）参数为null，则选择none

2 个答案: