Return all items that are only used once in table

Question

List the names of all ingredients that are used in only one recipe (1 column, 46 rows)

Logically the way I understand this query is that I need count the IngredientID 's in the Recipe_Ingredients column to find the instances where an IngredientID appears only once. But my query isn't returning any results.

I've tried substituting count(Ingredients.IngredientID) with count(*) and sum() . But both returned no results as well.

select Ingredients.IngredientName
from Ingredients
join Recipe_Ingredients on Ingredients.IngredientID = Recipe_Ingredients.RecipeID
group by Ingredients.IngredientName
having count(Ingredients.IngredientID) = 1;

DB Structure SQL File

DB Data SQL File

Answer 1

You're not joining on the correct column; it should be

Ingredients.IngredientID = Recipe_Ingredients.IngredientID

Making this change gives the correct result of 46 rows: demo

Note that preparing a dbfiddle as I did makes it a lot easier for others to answer your question.

Answer 2

Get the ingredients that are in the table of Recipe_Ingredients only once.

select * from Ingredients a where IngredientID in
(
select IngredientID
from Recipe_Ingredients 
group by IngredientID
having count(*) = 1
)

Answer 3

select Ingredients.IngredientName
from Ingredients
join Recipe_Ingredients on Ingredients.IngredientID = Recipe_Ingredients.IngredientID
group by Ingredients.IngredientName
having count(Ingredients.IngredientID) = 1;