SQL不存在问题

在处理查询中不存在的子句时遇到了一些问题。SQL不存在问题

我有三个表：

膳食

no_meal integer 
type_meal varchar(255)

消耗

no_meal integer 
designation varchar(255) 
quantity integer

食品

designation varchar(255) 
quantity integer 
type varchar(255)

食物中的数量是储存的数量，消耗的数量是消费量，所以它们会有所不同，因此自然的内部连接不会削减它。

食物类型可以是'饮料''肉''鱼'等。
类型餐可以是“早餐”“午餐”“晚餐”

我想要一个查询，会告诉我已在所有类型的饭菜被消耗的饮料。

我一直在切换和测试代码，但无法做到正确。目前我正在尝试这个：

SELECT Consumed.designation 
FROM Consumed 
WHERE NOT EXISTS 

(SELECT type_meal 
FROM Consumed, Food, Meal 
WHERE Consumed.designation = Food.designation 
AND Consumed.no_meal = Meal.no_meal 
AND type = 'Drink' 
ORDER BY Food.designation) 

EXCEPT 

(SELECT type_meal 
FROM Meal);

这到底是怎么回事？

感谢您的输入。

编辑：

我会为了更清楚地添加一些数据。

食品

Steak 100 Meat 
Water 200 Drink 
Coca cola 300 Drink

膳食

0001  Breakfast 
0002  Lunch 
0003  Dinner

消耗

0001  Water  50 
0002  Steak  20 
0001  Coca cola 20 
0003  Water  5 
0002  Water  15

现在，我想知道哪些DRI nk已经在每餐中消耗，只会给水。

希望我清除心中的一些有关该问题的

来源

2010-11-25 Martin

扭你的心一点点，并认为用双重否定....

我想[...]已在所有类型的饭菜被消耗的饮料。

你希望所有的饮品其中有没有一顿类型其中，酒后不吃饭类型的一部分：

select distinct f.designation 
from food f 
where 
    type = 'Drink' and 
    not exists (
    select * 
    from meal m1 
    where not exists (
     select * 
     from meal m2 
     join consumed c on c.no_meal = m2.no_meal 
     where 
     m1.no_meal = m2.no_meal and 
     c.designation = f.designation 
    ) 
)

这就是所谓的relational division。

来源

2010-11-25 20:55:20

现在我明白你想要什么...

SELECT designation 
FROM Food 
WHERE designation IN (
    SELECT designation 
    FROM Consumed 
    GROUP BY designation 
    HAVING Count(DISTINCT no_meal) = (
     SELECT Count(*) FROM Meal 
    ) 
) 
WHERE type = 'Drink'

来源

2010-11-25 18:40:09 Lucero

此查询不需要数量。我只是把它放在那里，因为它不同，自然的内部连接不能使用。 – Martin 2010-11-25 18:44:02

我需要的是在每种类型的餐中消费的“饮料”类型的食物名称。如果你不使用食物，你怎么区分饮料中的肉和鱼？ – Martin 2010-11-25 18:45:21

THANK YOUUUUUUUUUUUUUUUUUUUUUU :) That works;） – Martin 2010-11-25 20:01:04

我想要一个查询，会告诉我已在全部被消耗的饮料膳食类型。

您的编辑确实清除了一些东西。请注意，如果Consumed中的组合Designation, Type不是唯一的，那么下面的查询将不起作用，但我猜测它会是。

SELECT 
    c.Designation 
FROM 
    (SELECT 
     c.Designation 
    FROM  
     Consumed c 
    INNER JOIN 
     Meal m ON m.no_meal = c.no_meal 
    GROUP BY 
     c.Designation 
    HAVING 
     COUNT(*) = (SELECT COUNT(*) FROM Meal)) c 
INNER JOIN 
    Food f ON f.Designation = c.Designation 
WHERE 
    f.Type = 'Drink'

来源

2010-11-25 18:43:37

猜猜我没有足够的自我解释。我想要的不是每种饮料中饮料的数量按类型我想知道是否有任何饮料在所有类型的餐中消耗。我会将一些示例数据添加到主页面以便更好地解释 – Martin 2010-11-25 18:54:53

编辑完成后，您的原始解释实际上很有意义。我改变了陈述。你能证实结果吗？ – 2010-11-25 19:30:51

select * 
from food f inner join 
    consumed c_1 on c_1.designation = f.designation 
where type='Drink' and 
not exists -- to filter out drinks that are not a part of all the meals 
(select 1 
from consumed c_2 inner join 
    meal m_1 on m_1.no_meal = c_2.no_meal 
where c_1.no_meal = c2.no_meal and 
     c_1.designation = c2.designation and 
not exists (select 1 
       from meal m_2 
       where m_1.no_meal = m_2.no_meal))

来源

2010-11-25 18:54:07

我想要一个查询，会告诉我已在所有类型的饭菜被消耗的饮料。

这里是模型结构和插入你的建议：

USE SqlTests 
GO 

CREATE TABLE Meal (
    no_meal int 
    , type_meal nvarchar(255) 
) 
GO 

insert into Meal (no_meal, type_meal) 
    values (1, N'Breakfast') 
GO 
insert into Meal (no_meal, type_meal) 
    values(2, N'Lunch') 
GO 
insert into Meal (no_meal, type_meal) 
    values(3, N'Dinner') 
GO 

CREATE TABLE Consumed (
    no_meal int 
    , designation nvarchar(255) 
    , quantity int 
) 
GO 

insert into Consumed (no_meal, designation, quantity) 
    values (1, N'Water', 50) 
GO 
insert into Consumed (no_meal, designation, quantity) 
    values (2, N'Steak', 20) 
GO 
insert into Consumed (no_meal, designation, quantity) 
    values (1, N'Coca cola', 20) 
GO 
insert into Consumed (no_meal, designation, quantity) 
    values(3, N'Water', 5) 
GO 
insert into Consumed (no_meal, designation, quantity) 
    values(2, N'Water', 15) 
GO 

CREATE TABLE Food (
    designation nvarchar(255) 
    , quantity int 
    , [type] nvarchar(255) 
) 
GO 

insert into Food (designation, quantity, [type]) 
    values (N'Water', 200, N'Drink') 
GO 
insert into Food (designation, quantity, [type]) 
    values (N'Steak', 100, N'Meat') 
GO 
insert into Food (designation, quantity, [type]) 
    values (N'Coca cola', 200, N'Drink') 
GO

然后，所提出的SELECT选择：

select c.designation 
    from Consumed c 
     inner join Meal m on m.no_meal = c.no_meal 
     inner join Food f on f.designation = c.designation and f.[type] LIKE N'Drink' 
    group by c.designation 
     having COUNT(c.designation) = (select COUNT(type_meal) from Meal)

回报（至少在我的数据库引擎（SQL Server Express的2005年）

Water

我的信息数据是否正确？

来源

2010-11-25 19:14:50

SQL不存在问题

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