Question

我目前正在努力解决SQL查询问题。我想知道有人能提供帮助吗？

我正在尝试将字符串传递给存储过程之一并基于此我想在WHERE子句中稍微修改查询

param字符串可以是Alphabets或Category ID

ALTER procedure [dbo].[procProductShow]
    @Alphabet varchar(3) = 'ALL' 
AS
    IF @Alphabet =  'ALL' or @Alphabet = 'A' OR @Alphabet = 'B' OR  @Alphabet = 'C' --- UNTIL Z
        SELECT 
            Product.ProdID, 
            Product.ProdImgThumbnailLoc, 
            Product.ProdImgThumbnailAltText

        FROM 
            ProductCategory 
            INNER JOIN Product ON ProductCategory.ProdID = Product.ProdID 
            INNER JOIN Category ON ProductCategory.CatID = Category.CatID 

        WHERE 
            Product.ProdShowOnWeb = 1 AND 
            Category.ShowOnReport = 1 AND               
             (@Alphabet = 'ALL' OR Product.ProdHeading LIKE @Alphabet + '%')    
        ORDER BY Product.ProdHeading

    ELSE
        SELECT 
            Product.ProdID, 
            Product.ProdImgThumbnailLoc, 
            Product.ProdImgThumbnailAltText 

        FROM 
            ProductCategory 
            INNER JOIN Product ON ProductCategory.ProdID = Product.ProdID 
            INNER JOIN Category ON ProductCategory.CatID = Category.CatID               
        WHERE 
            Product.ProdShowOnWeb = 1 AND 
            Category.ShowOnReport = 1 AND               
            Category.CatId = @Alphabet          
        ORDER BY Product.ProdHeading

Answer 1

您实际上可以简化此查询，以便您不需要执行长IF语句：

ALTER procedure [dbo].[procProductShow]
    @Alphabet varchar(3) = 'ALL' 
AS
    SELECT 
        Product.ProdID, 
        Product.ProdImgThumbnailLoc, 
        Product.ProdImgThumbnailAltText
    FROM 
        ProductCategory 
        INNER JOIN Product ON ProductCategory.ProdID = Product.ProdID 
        INNER JOIN Category ON ProductCategory.CatID = Category.CatID 
    WHERE 
        Product.ProdShowOnWeb = 1 AND 
        Category.ShowOnReport = 1 AND               
         (@Alphabet = 'ALL' 
             OR (@Alphabet LIKE '[A-Z]' AND Product.ProdHeading LIKE @Alphabet + '%') 
             OR Category.CatId = @Alphabet) 
    ORDER BY Product.ProdHeading

WHERE条件的@Alphabet LIKE '[A-Z]'部分将执行正则表达式以检查@Alphabet是否仅包含＆＃39; A＆＃39;通过＆＃39; Z＆＃39;

使用WHEN OR IF语句的SQL语句

1 个答案: