Question

I have 2 tables :

Ingredients with the following fields:

ID(numeric) Ingredient(text) Plural(text)

where Ingredient is the name of the ingredient and Plural is its plural name(ex:olive,olives)

and another table Shopping_Ingredients with the fields:

Amount(numeric) , Ingredient_ID(numeric)

I need a SQL statement that returns the added value of Amount for all the table Shopping_Ingredients and the Ingredient name (singular when it doesn’t have plural or plural when it does)

example :

Ingredients :

1 ‘apple’ ‘apples’

2 ‘garlic’ ”

Shopping_Ingredients:

1 1

2 1

3 1

2 2

3 2

return :

6 ‘apples’

5 ‘garlic’

Answer 1

Since You didn’t specify what database engine You use, here is version of query that works on SQL Server 2000 and newer (probably works on MySQL also):

SELECT 
    T.Amount, 
    CASE 
        WHEN T.Amount <= 1 THEN I.Ingredient
    ELSE 
        CASE WHEN ISNULL(I.Plural, '') = '' THEN I.Ingredient ELSE I.Plural END
    END
FROM
(
    SELECT SUM(Amount) Amount, Ingredient_ID FROM Shopping_Ingredients GROUP BY Ingredient_ID
) AS T
INNER JOIN Ingredient I ON
    I.Ingredient_ID = T.Ingredient_ID

And here for SQL Server 2005 and newer:

;WITH CTE
AS
(
    SELECT SUM(Amount) Amount, Ingredient_ID FROM Shopping_Ingredients GROUP BY Ingredient_ID
)
SELECT 
    T.Amount, 
    CASE 
        WHEN T.Amount <= 1 THEN I.Ingredient
    ELSE 
        CASE WHEN ISNULL(I.Plural, '') = '' THEN I.Ingredient ELSE I.Plural END
    END
FROM CTE AS T
INNER JOIN Ingredient I ON
    I.Ingredient_ID = T.Ingredient_ID