Question

所以，我有3张桌子：

PIZZA 与pizza_ID，pizza_title和pizza_price
INGREDIENTS with ingredients_ID; ingredients_title和ingredients_description
PIZZA_INGREDIENTS ID，pizza_id，ingredients_id

我需要从PIZZA中选择包含2种成分的所有pizza_title。现在，我有这个：

SELECT pizza.pizza_ID, pizza.pizza_title, pizza.pizza_price, pizza_ingredients.ingredient_id
FROM pizza
JOIN pizza_ingredients ON pizza_ingredients.pizza_id=pizza.id
WHERE pizza_ingredients.ingredient_id='7' or pizza_ingredients.id='4'
GROUP BY pizza.id

此代码返回所有含有成分7或成分4的比萨饼。我只需要有7和4的比萨...

SQL不是我的强项，我感谢任何帮助。感谢

Answer 1

尝试加入子查询，该子查询进行聚合以查找具有两种成分的所有比萨饼：

SELECT p1.*
FROM pizza p1
INNER JOIN
(
    SELECT pizza_id
    FROM pizza_ingredients
    GROUP BY pizza_id
    HAVING COUNT(*) = 2
) p2
    ON p1.pizza_id = p2.pizza_id;

如果我误解了你的问题的措辞，而你想要找到所有有两种特殊成分的披萨，而不考虑其他成分，那么请使用这个查询：

SELECT p1.*
FROM pizza p1
INNER JOIN
(
    SELECT pizza_id
    FROM pizza_ingredients
    WHERE ingredients_id IN (4, 7)
    GROUP BY pizza_id
    HAVING COUNT(DISTINCT ingredients_id) = 2
) p2
    ON p1.pizza_id = p2.pizza_id;

我的MySql查询需要帮助（从多个表中选择）

1 个答案: