加入三个表，查询在 SQLite 中没有按预期工作

Question

我正在构建一个按成分搜索食谱的应用。我有 5 张桌子：

食谱

RecipeId | RecipeTitle | Directions | PrepTime | CookTime

成分

IngredientId | IngredientName

类别

CategoryId | CategoryName

RecipeIngredient 联结表（多对多）

RecipeId | IngredientId | Quantity | UOM | Comments

RecipeCategory 联结表（多对多）

RecipeId | CategoryId

我想做的是让用户选择成分、类别和时间，应用程序将搜索适合用户输入的食谱。在我的应用程序中实现之前，我正在测试它如何使用 DB Browser for SQLite 工作，但它没有按预期工作。

这是我尝试过的最新查询（当然我假设用户在这里输入，他们不受他们可以选择的成分和类别数量的限制）：

SELECT RecipeTitle, COUNT(RecipeTitle) AS Ing FROM Recipe

JOIN RecipeIngredient ON Recipe.RecipeId = RecipeIngredient.RecipeId
JOIN RecipeCategory ON Recipe.RecipeId = RecipeCategory.RecipeId

WHERE
    RecipeIngredient.IngredientId = 
    (SELECT Ingredient.IngredientId FROM Ingredient
    WHERE Ingredient.IngredientName = "olive oil")
OR
    RecipeIngredient.IngredientId = 
    (SELECT Ingredient.IngredientId FROM Ingredient
    WHERE Ingredient.IngredientName = "beef")
OR
    RecipeIngredient.IngredientId = 
    (SELECT Ingredient.IngredientId FROM Ingredient
    WHERE Ingredient.IngredientName = "parsley")
AND
    RecipeCategory.CategoryId = 
    (SELECT Category.CategoryId FROM Category
    WHERE Category.CategoryName = "Dinner")
AND
    Recipe.PrepTime + Recipe.CookTime < 35 -- In minutes

GROUP BY RecipeTitle
ORDER BY Ing DESC -- Orders results by recipes that have the most out of the ingredients the user chose, with less relevant recipes at the bottom

以下是我遇到的问题：

• 我希望 COUNT(RecipeTitle) 计算结果中每个食谱中选择的成分的数量，但它也计算类别。
• 类别和时间搜索不起作用。它确实显示了包含所选成分的食谱，但也显示了不是Dinner 并且需要总时间为 35 分钟或以上的食谱。

Answer 1

试试

SELECT RecipeTitle, COUNT(Ingredient.IngredientId) AS Ing 
FROM Recipe
JOIN RecipeIngredient ON Recipe.RecipeId = RecipeIngredient.RecipeId
JOIN RecipeCategory ON Recipe.RecipeId = RecipeCategory.RecipeId
JOIN Ingredient ON RecipeIngredient.IngredientId = Ingredient.IngredientId 
JOIN Category ON CategoryCategoryId = RecipeCategory.CategoryId
WHERE Ingredient.IngredientName IN ('olive oil', 'beef', 'parsley')
AND Category.CategoryName = 'Dinner'
AND (Recipe.PrepTime + Recipe.CookTime) < 35
GROUP BY RecipeTitle
ORDER BY Ing DESC