Question

我正在构建一个食谱网站，我正在尝试创建一个带有表值参数的存储过程，但遇到了一些问题。

因此，TVP 是根据用户在尝试搜索食谱时选择的复选框列表来填充的。然后我想根据这些选择显示食谱，因此我在存储过程中使用了 TVP。

但是，当用户未在复选框列表之一中选择任何选项时，我希望查询显示所有记录（对于每个部分）。当我尝试执行此操作时，查询立即不返回任何结果。

TVP 设置和逻辑

<头>

类别	难度	持续时间
肉	简单	0-15 分钟
string.Empty	平均	30-45 分钟
鱼	硬	string.Empty

我希望程序通过在类别、难度和持续时间中选择的所有选项过滤每个食谱。 IE。在这种情况下，我希望存储过程返回所有具有 Category = "Meat" 或 "Fish" 的食谱；难度 =“简单”或“平均”或“难”，持续时间 =“0-15 分钟”或“30-45 分钟”。

例如，如果 Category 中不存在任何值，则存储过程应返回所有类别的配方，并且仅根据具有值的列进行过滤。

目前的工作代码

ALTER PROCEDURE uspPesquisarReceita (@TVP dbo.Filters READONLY)
AS
BEGIN
    SELECT R.RecipeName, C.Category, DF.Dificulty, D.Duration, R.Rating, R.Publication, R.Photo, R.Views, R.IDRecipe
        FROM dbo.Recipes R 
        LEFT JOIN dbo.Categories C ON R.IDCategory = C.IDCategory 
        LEFT JOIN dbo.Dificulty DF ON R.IDDificulty = DF.IDDificulty
        LEFT JOIN dbo.Duration D ON R.IDDuration = D.IDDuration
        WHERE R.IDStatus = 1 
        AND (C.Category IN (SELECT Category FROM @TVP)
        AND DF.Dificulty IN (SELECT Dificulty FROM @TVP) 
        AND D.Duration IN (SELECT Duration FROM @TVP))
END

此代码有效，仅当我在所有三个复选框列表（称为类别、难度和持续时间）中选择选项时。

我尝试过的代码 #1

ALTER PROCEDURE uspPesquisarReceita (@TVP dbo.Filters READONLY)
    AS
    BEGIN
        SELECT R.RecipeName, C.Category, DF.Dificulty, D.Duration, R.Rating, R.Publication, R.Photo, R.Views, R.IDRecipe
            FROM dbo.Recipes R 
            LEFT JOIN dbo.Categories C ON R.IDCategory = C.IDCategory 
            LEFT JOIN dbo.Dificulty DF ON R.IDDificulty = DF.IDDificulty
            LEFT JOIN dbo.Duration D ON R.IDDuration = D.IDDuration
            WHERE R.IDStatus = 1 
            AND (C.Category IN (CASE WHEN NOT EXISTS (SELECT Category FROM @TVP)
                                 THEN
                                  (SELECT R.RecipeName, C.Category, DF.Dificulty, D.Duration, 
                                  R.Rating, R.Publication, R.Photo, R.Views, R.IDRecipe
                                  FROM dbo.Recipes R 
                                  LEFT JOIN dbo.Categories C ON R.IDCategory = C.IDCategory 
                                  LEFT JOIN dbo.Dificulty DF ON R.IDDificulty = DF.IDDificulty
                                  LEFT JOIN dbo.Duration D ON R.IDDuration = D.IDDuration
                                  WHERE R.IDStatus = 1)
                                 ELSE (SELECT Category FROM @TVP) 
            AND DF.Dificulty IN (SELECT Dificulty FROM @TVP)
                                  *same as above*
            AND D.Duration IN (SELECT Duration FROM @TVP))
                                  *same as above*
    END

我尝试过的代码#2（仅以类别为例）

ALTER PROCEDURE uspPesquisarReceita (@TVP dbo.Filters READONLY)
        AS
        BEGIN
            IF NOT EXISTS (SELECT Category FROM @TVP)
                SELECT R.RecipeName, C.Category, DF.Dificulty, D.Duration, R.Rating, 
                R.Publication, R.Photo, R.Views, R.IDRecipe
                FROM dbo.Recipes R 
                LEFT JOIN dbo.Categories C ON R.IDCategory = C.IDCategory 
                LEFT JOIN dbo.Dificulty DF ON R.IDDificulty = DF.IDDificulty
                LEFT JOIN dbo.Duration D ON R.IDDuration = D.IDDuration
                WHERE R.IDStatus = 1
                AND DF.Dificulty IN (SELECT Dificulty FROM @TVP) 
                AND D.Duration IN (SELECT Duration FROM @TVP))
            ELSE
                SELECT R.RecipeName, C.Category, DF.Dificulty, D.Duration, R.Rating, 
                R.Publication, R.Photo, R.Views, R.IDRecipe
                FROM dbo.Recipes R 
                LEFT JOIN dbo.Categories C ON R.IDCategory = C.IDCategory 
                LEFT JOIN dbo.Dificulty DF ON R.IDDificulty = DF.IDDificulty
                LEFT JOIN dbo.Duration D ON R.IDDuration = D.IDDuration
                WHERE R.IDStatus = 1 
                AND (C.Category IN (SELECT Category FROM @TVP)
                AND DF.Dificulty IN (SELECT Dificulty FROM @TVP) 
                AND D.Duration IN (SELECT Duration FROM @TVP))
    END

这两次尝试都没有产生任何结果。你能帮我吗？我错过了什么？

谢谢！

Answer 1

我将建议类似以下内容 - 尽管正如 Dale 所指出的那样，当 @TVP 值填充不同的过滤器组合时，查看它的确切外观会很方便。但是，在此期间，请尝试一下，看看会得到什么结果。

ALTER PROCEDURE uspPesquisarReceita (@TVP dbo.Filters READONLY)
AS
BEGIN
    SELECT R.RecipeName, C.Category, DF.Dificulty, D.Duration, R.Rating, R.Publication, R.Photo, R.Views, R.IDRecipe
        FROM dbo.Recipes R 
        LEFT JOIN dbo.Categories C ON R.IDCategory = C.IDCategory 
        LEFT JOIN dbo.Dificulty DF ON R.IDDificulty = DF.IDDificulty
        LEFT JOIN dbo.Duration D ON R.IDDuration = D.IDDuration
        WHERE R.IDStatus = 1 
        AND
        (
            (C.Category IN (SELECT Category FROM @TVP))
            OR
            (NOT EXISTS (SELECT 1 FROM @TVP WHERE LTRIM(ISNULL(Category, '')) <> ''))
        )
        AND 
        (
            (DF.Dificulty IN (SELECT Dificulty FROM @TVP))
            OR
            (NOT EXISTS (SELECT 1 FROM @TVP WHERE LTRIM(ISNULL(Dificulty, '')) <> ''))
        )
        AND 
        (
            (D.Duration IN (SELECT Duration FROM @TVP))
            OR
            (NOT EXISTS (SELECT 1 FROM @TVP WHERE LTRIM(ISNULL(Duration, '')) <> ''))
        )
END

基本上，我假设如果用户没有勾选特定过滤器的任何选项（类别、难度或持续时间），那么@TVP 表中将不会有相应列中有值的行。（如果此假设不正确，那么我们将回到 Dale 的建议，即查看有关如何填充 @TVP 变量的更多详细信息 - 即您的应用程序端代码）

带 TVP 参数的条件 WHERE 子句

1 个答案: