Brian Dunning wrote:
How do I query "How many calories did Brian eat on 2009-09-04"?

Table:People
+-----------+-------+
+ Person_ID + Name  |
+-----------+-------+
| 5         | Brian |
+-----------+-------+

Table:Meals
+---------+-----------+-----------+------------+
| Meal_ID | Person_ID | Meal_Name | Date       |
+---------+-----------+-----------+------------+
| 3       | 5         | Breakfast | 2009-09-04 |
| 4       | 5         | Lunch     | 2009-09-04 |
+---------+-----------+-----------+------------+

Table:Meal_Items
+-------------+---------+-----------+----------+
| MealItem_ID | Meal_ID | Item_Name | Calories |
+-------------+---------+-----------+----------+
| 16          | 3       | Banana    | 100      |
| 17          | 3       | Milk      | 150      |
| 18          | 4       | Cookie    | 200      |
+-------------+---------+-----------+----------+



SELECT sum(calories) from People
INNER JOIN Meals ON People.Name=Meals.Name
INNER JOIN Meal_Items on Meals.Meal_ID=Meal_Items.Meal_ID
WHERE Name='Brian' AND Date='2009-09-04';

--
Gerald L. Clark
Sr. V.P. Development
Supplier Systems Corporation
Unix  since 1982
Linux since 1992

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