Question

I have 3 tables with this structure:

Recipe

id | recipe_name

Ingredients

id | ingredients_name

Relationship

rid | recipe_id | ingredients_id

Example i search for recipe’s with an ingredient of “chicken” and “mayonnaise” then it will display all the recipe’s having this two ingredients. i already get the code for that:

SELECT * from recipe r
INNER JOIN relationship ri on r.id=ri.recipe_id
INNER JOIN ingredients i on i.id=ri.ingredients_id
WHERE i.ingredients_name IN ('chicken','mayonnaise')
GROUP BY r.id

But what I want is that when a recipe contains only chicken and mayonnaise as its ingredients, it must display on a separate result. How can i do that?

Answer 1

By adding a HAVING clause – like so:

SELECT * from recipe r
INNER JOIN relationship ri on r.id=ri.recipe_id
INNER JOIN ingredients i on i.id=ri.ingredients_id
GROUP BY r.id
HAVING COUNT(DISTINCT i.ingredients_name)=2 AND
       COUNT(DISTINCT case when i.ingredients_name IN ('chicken','mayonnaise') 
                           then i.ingredients_name end)=2

(Note: this will return recipes that only include both chicken and mayonnaise, and no other ingredients. To return recipes that include both chicken and mayonnaise, but that could also include other ingredients, remove the COUNT(DISTINCT case condition and reinstate the WHERE clause.)