Question

我有这个复杂的查询，正在获得当前的库存水平＆amp;将单位转换为英镑，然后查看未完成的订单和将单位转换为磅，最后显示所有未完成订单的每种成分所需的总金额。

目的是列出具有库存水平的成分，然后列出履行所有未完成订单所需的金额。如果面包师没有足够的面粉，那么他可以看到这一点，并在他开始烘焙当天之前考虑采购更多。

问题在于，当我运行此查询时，它正在跳过组函数中的第一行。当我在没有分组的情况下运行它时，它会使所有行都正确，但是当我使用SUM和GROUP BY运行它时，它会跳过第一行，因此它会计算项目所需的值。有小费吗？谢谢！

SELECT 
    inventory.id, 
    inventory.title, 
    products.weight, 
    products.id AS product_id, 
    (orders_items.quantity - orders_items.quantity_baked) AS quantity_to_be_baked,
    (SELECT @inventory_pounds:=
        CASE inventory.units
            WHEN  'kilograms'
            THEN 2.20462 * inventory.quantity
            WHEN  'pounds'
            THEN 1 * inventory.quantity
            WHEN  'ounces'
            THEN 0.0625 * inventory.quantity
            WHEN  'grams'
            THEN 0.00220462 * inventory.quantity
        END ) as inventory_pounds,
    (SELECT @dough_recipe_ingredient_pounds:=
        CASE dough_recipes.units
            WHEN 'kilograms'
            THEN 2.20462 * dough_recipes.amount
            WHEN 'pounds'
            THEN 1 * dough_recipes.amount
            WHEN 'ounces'
            THEN 0.0625 * dough_recipes.amount
            WHEN 'grams'
            THEN 0.00220462 * dough_recipes.amount
        END ) AS dough_recipe_ingredient_pounds, 
    (orders_items.quantity - orders_items.quantity_baked) AS num_loaves_needed,
    ( SELECT @dough_recipe_yield_pounds:=
        CASE doughs.units
            WHEN 'kilograms'
            THEN 2.20462 * doughs.yield
            WHEN 'pounds'
            THEN 1 * doughs.yield
            WHEN 'ounces'
            THEN 0.0625 * doughs.yield
            WHEN 'grams'
            THEN 0.00220462 * doughs.yield
        END ) AS dough_recipe_yield_pounds,
    (SELECT SUM( @dough_recipe_ingredient_pounds / @dough_recipe_yield_pounds * weight * (orders_items.quantity - orders_items.quantity_baked))) as amount_needed_for_orders
    FROM inventory
    LEFT JOIN dough_recipes ON inventory.id = dough_recipes.inventory_id
    LEFT JOIN products ON dough_recipes.dough_id = products.dough_id
    LEFT JOIN orders_items ON products.id = orders_items.product_id AND (orders_items.quantity - orders_items.quantity_baked) > 0
    LEFT JOIN doughs ON doughs.id = products.dough_id
    GROUP BY id

Answer 1

Group by不会跳过行或任何内容。你的查询结构似乎错了。尝试一下这个：

SELECT SUM(dough_recipe_ingredient_pounds / dough_recipe_yield_pounds * weight * (quantity - quantity_baked))) as amount_needed_for_orders
FROM (
    SELECT 
    inventory.id, 
    inventory.title, 
    products.weight, 
    products.id AS product_id, 
    orders_items.quantity,
    orders_items.quantity_baked,
    (orders_items.quantity - orders_items.quantity_baked) AS quantity_to_be_baked,
        CASE inventory.units
            WHEN  'kilograms'
            THEN 2.20462 * inventory.quantity
            WHEN  'pounds'
            THEN 1 * inventory.quantity
            WHEN  'ounces'
            THEN 0.0625 * inventory.quantity
            WHEN  'grams'
            THEN 0.00220462 * inventory.quantity
        END as inventory_pounds,
        CASE dough_recipes.units
            WHEN 'kilograms'
            THEN 2.20462 * dough_recipes.amount
            WHEN 'pounds'
            THEN 1 * dough_recipes.amount
            WHEN 'ounces'
            THEN 0.0625 * dough_recipes.amount
            WHEN 'grams'
            THEN 0.00220462 * dough_recipes.amount
        END  AS dough_recipe_ingredient_pounds, 
    (orders_items.quantity - orders_items.quantity_baked) AS num_loaves_needed,
        CASE doughs.units
            WHEN 'kilograms'
            THEN 2.20462 * doughs.yield
            WHEN 'pounds'
            THEN 1 * doughs.yield
            WHEN 'ounces'
            THEN 0.0625 * doughs.yield
            WHEN 'grams'
            THEN 0.00220462 * doughs.yield
        END AS dough_recipe_yield_pounds
    FROM inventory
    LEFT JOIN dough_recipes ON inventory.id = dough_recipes.inventory_id
    LEFT JOIN products ON dough_recipes.dough_id = products.dough_id
    LEFT JOIN orders_items ON products.id = orders_items.product_id AND (orders_items.quantity - orders_items.quantity_baked) > 0
    LEFT JOIN doughs ON doughs.id = products.dough_id
) sq
GROUP BY id

如果这对您正在寻找的内容确实是正确的查询，我们无法在没有样本数据和所需结果的情况下进行分析。以上查询只是基于您的查询的猜测。

Answer 2

我会盲目地试一试，因为我无法在没有小提琴的情况下进行测试。（我实际上可以，但我太懒了）

有时格式错误的group by会隐藏您的数据，请尝试以下操作，看看是否有帮助。

GROUP BY inventory.id, products.id

MYSQL复杂的GROUP BY和SUM查询失败

2 个答案: