Question

我是SQL的初学者，尤其是TSQL。我需要为SQL Server 2008编写一个SP，它将读取符合某些条件的所有记录，然后在不同的结果集中读取它们的相关类别，成分，单位等。为了阅读一个元素我的SP是：

-- Select the recipe 
SELECT Recipe.*
FROM Recipe
WHERE Recipe.RecipeId = @RecipeId

-- Select the categories themselves
SELECT Category.*
FROM Category
JOIN RecipeCategory ON RecipeCategory.CategoryId = Category.CategoryId
WHERE RecipeCategory.RecipeId = @RecipeId

-- Select the ingredient information for the recipe
SELECT RecipeIngredient.*
FROM RecipeIngredient
JOIN Recipe ON Recipe.RecipeId = RecipeIngredient.RecipeId
WHERE Recipe.RecipeId = @RecipeId

-- Select the ingredients themselves
SELECT Ingredient.* 
FROM Ingredient 
JOIN RecipeIngredient ON RecipeIngredient.IngredientId = Ingredient.IngredientId
JOIN Recipe ON Recipe.RecipeId = RecipeIngredient.RecipeId
WHERE Recipe.RecipeId = @RecipeId  

-- Select the units that are associated with the ingredients    
SELECT Unit.*
FROM Unit
JOIN Ingredient ON Ingredient.UnitId = Unit.UnitId
JOIN RecipeIngredient ON RecipeIngredient.IngredientId = Ingredient.IngredientId
WHERE RecipeIngredient.RecipeId = @RecipeId

如何将其转换为阅读具有Name like '%..%'

的所有食谱

由于该表有数百万个食谱，我希望尽可能高效地完成。

Answer 1

要按名称（带通配符）选择食谱，您可能会改变您的过程以执行以下操作：

-- Get a list of name-matched RecipeIDs
DECLARE @RecipeIDs TABLE (
    RecipeID int not null primary key
)
INSERT INTO @RecipeIDs (RecipeID)
SELECT Recipe.RecipeID
FROM Recipe
-- Change the parameter of the proc from @RecipeId to @Name
WHERE Recipe.Name like '%' + @Name + '%'

-- Select the recipes 
SELECT Recipe.*
FROM Recipe
WHERE Recipe.RecipeId in (select RecipeID from @RecipeIDs)

-- Select the categories themselves
SELECT Category.*
FROM Category
    JOIN RecipeCategory ON RecipeCategory.CategoryId = Category.CategoryId
WHERE RecipeCategory.RecipeId in (select RecipeID from @RecipeIDs)

-- Select the ingredient information for the recipes
SELECT RecipeIngredient.*
FROM RecipeIngredient
    JOIN Recipe ON Recipe.RecipeId = RecipeIngredient.RecipeId
WHERE Recipe.RecipeId in (select RecipeID from @RecipeIDs)

-- Select the ingredients themselves
SELECT Ingredient.* 
FROM Ingredient 
    JOIN RecipeIngredient ON RecipeIngredient.IngredientId = Ingredient.IngredientId
    JOIN Recipe ON Recipe.RecipeId = RecipeIngredient.RecipeId
WHERE Recipe.RecipeId in (select RecipeID from @RecipeIDs)  

-- Select the units that are associated with the ingredients    
SELECT Unit.*
FROM Unit
    JOIN Ingredient ON Ingredient.UnitId = Unit.UnitId
    JOIN RecipeIngredient ON RecipeIngredient.IngredientId = Ingredient.IngredientId
WHERE RecipeIngredient.RecipeId in (select RecipeID from @RecipeIDs)

我首先获取与新@Name参数匹配的所有配方ID，然后使用IN而不是=获取结果集。

就性能而言，请确保在尝试优化速度之前先获得正确的结果。但是，如果遇到性能问题，还可以使用其他方法编写查询。例如，如果匹配的ID列表变得很大，您可能更倾向于使用临时表而不是表变量来保留列表，或者只是将名称匹配部分串联到每个选择中。也许RecipeID上的连接会比IN更快。当然，在所有这些情况下，SQL引擎可能会做同样的事情（毕竟SQL基本上是declarative。表的索引也可以发挥作用。请告诉我们这对您有何影响。

TSQL：存储过程，用于检索多个记录和引用表中的数据

1 个答案: