Question

我有以下sql图：

Category:
id_category
category_name

Measurement
id_measurement
name_measurement

Ingredient
id_ingredient
name_ingredient
category_id
measurement_id
nrOfCal

IngredientCake
id_ingredient
cake_code
quantities

Cake
cake_code
cake_name

我不知道如何显示所有代码和名称少于500卡路里的蛋糕。我尝试了什么：

select [Cake].cake_code , [Cake].cake_name 
from       [Cake] 
inner join [Ingredient_Cake] 
on         ([Cake].cake_code = [Ingredient_Cake].cake_code)
inner join [Ingredient] 
on         ([Ingredient_Cake].id_ingredient = [Ingredient].id_ingredient)
where      sum([Ingredient].nrOfCal) < 500 
group by   [Cake].cake_code;

但无论如何它给了我错误：

An aggregate may not appear in the WHERE clause unless it is in a subquery contained in a HAVING clause or a select list, and the column being aggregated is an outer reference.

任何解决方案？

编辑：

 select     [Cake].cake_code, 
       [Cake].cake_name 
 from       [Cake] 
 inner join [Ingredient_Cake] 
 on         ([Cake].cake_code = [Ingredient_Cake].cake_code)
 inner join [Ingredient] 
 on         ([Ingredient_Cake].id_ingredient = [Ingredient].id_ingredient)
 group by   [Cake].cake_code, [Cake].cake_name
 having     sum(nrOfCal*quantities) > 500;

我已经编辑了，现在有趣的部分是，如果我这样做，它会返回我应该如何，卡路里低于500的蛋糕，但现在条件是（＆gt; 500），如果我改变条件为＆lt; 500，它只给我带来超过500卡路里的蛋糕。发生了什么事？

Answer 1

尝试将聚合移动到having子句：

select     [Cake].cake_code, 
           [Cake].cake_name 
from       [Cake] 
inner join [Ingredient_Cake] 
on         ([Cake].cake_code = [Ingredient_Cake].cake_code)
inner join [Ingredient] 
on         ([Ingredient_Cake].id_ingredient = [Ingredient].id_ingredient)
group by   [Cake].cake_code, [Cake].cake_name
having     sum([Ingredient].nrOfCal) < 500;

Answer 2

由于您的条件是汇总值，因此您需要使用HAVING子句（在group by之后执行）而不是where：

select [Cake].cake_code , [Cake].cake_name from [Cake] 
inner join [Ingredient_Cake] on ([Cake].cake_code = 
[Ingredient_Cake].cake_code)
inner join [Ingredient] on ([Ingredient_Cake].id_ingredient 
= [Ingredient].id_ingredient)
group by [Cake].cake_code
Having sum([Ingredient].nrOfCal) < 500

所有的蛋糕总和少于一组

2 个答案: