Question

我正在尝试计算子查询中的匹配数量，以便按结果排序。

我正在尝试查询：

SELECT recipes.*, (SELECT COUNT(ingredient_id) FROM recipes WHERE ingredient_id IN(1,3))            AS ingredient_matches 
FROM recipes 
INNER JOIN ingredients 
ON recipes.id = ingredients.recipe_id 
INNER JOIN ingredients_available 
ON ingredients.ingredient_id = ingredients_available.id
GROUP BY recipes.id 
ORDER BY ingredient_matches DESC;

数据库结构：

recipes:
id, name
ingredients:
id, recipe_id, ingredient_id
ingredients_available:
id, name
tags:
id, recipe_id, tag_id
tags_available:
id, name

下面的查询有效，但我希望能够拥有不匹配的访问成分，所以我可以说如果有意义的话他们需要它们吗？

SELECT recipes.*, COUNT(ingredients.id) AS ingredient_matches 
FROM recipes 
INNER JOIN ingredients 
ON recipes.id = ingredients.recipe_id 
INNER JOIN ingredients_available 
ON ingredients.ingredient_id = ingredients_available.id
WHERE ingredient_id IN (1, 5) 
GROUP BY recipes.id 
ORDER BY ingredient_matches DESC;

Answer 1

http://sqlfiddle.com/#!2/3f9ef/15

是理想的结果。这是因为我没有确定子查询中的recipes_id = ingredients.recipe_id。

Answer 2

以下是否有效？：

SELECT recipes.*, COUNT(ingredients.id) AS ingredient_matches 
FROM recipes 
INNER JOIN ingredients 
ON recipes.id = ingredients.recipe_id 
LEFT JOIN ingredients_available 
ON ingredients.ingredient_id = ingredients_available.id
WHERE ingredient_id IN (1, 5) 
GROUP BY recipes.id 
ORDER BY ingredient_matches DESC;

计算子查询中的匹配数量，以便按顺序排序查询

2 个答案: