Need to further refine my output to my SQL query - sql

Question

I am working on an assignment for class and I have hit a roadblock. This is my code that I am working with:
SELECT ANIM_ID, ANIM_NAME, FOOD_ITEM_ID, FOOD_ITEM_DESCRIPTION, FOOD_CATEGORY_DESCRIPTION, FOOD_PRICE
FROM ANIMAL
JOIN ANIMAL_DIETARY_REQUIREMENTS USING (ANIM_ID)
JOIN FOOD_ITEM USING (FOOD_ITEM_ID)
JOIN FOOD_CATEGORY USING (FOOD_CATEGORY_ID)
JOIN FOOD_ITEM_SUPPLIER USING (FOOD_ITEM_ID)
WHERE ANIM_NAME = 'Brianna' OR ANIM_NAME = 'Isaiah'
AND FOOD_PRICE IN
(SELECT MIN(FOOD_PRICE)
FROM FOOD_ITEM_SUPPLIER
GROUP BY FOOD_ITEM_ID);
And the result I am getting is this:(truncating only the columns I am concerned with)
"ANIM_NAME""FOOD_ITEM_ID""FOOD_ITEM_DESCRIPTION""FOOD_PRICE"
"Brianna" "121" "Super Mixed Seafood ""241.99"
"Brianna" "4" "Tasty Meat with Antioxi""384.76"
"Brianna" "4" "Tasty Meat with Antioxi""297.73"
"Isaiah" "9" "Nutritious Chicken" ""51.97"
"Brianna" "4" "Tasty Meat with Antioxi""48.4"
"Isaiah" "61" "Nutritious Mixed Seafoo""421.63"
I am getting all prices for Brianna and tasty meat instead of just the min price. I just need the rows that are in bold. I have been at this all day and I just can't see the answer and I am sure it is a simple line of code that I am just missing. This is my first Database class and my first time coding with SQL. Also this is my very first post so if I posted something in error I do apologize. Thanks for any help or feedback you guys might have for me.

Answer 1

First, you need parentheses around your animal name selection. As it was, you asked for all the prices for Brianna, or all the prices for Isaiah which were min prices, which was exactly what you got.
Second, you need to compare the min price for a given FOOD_ITEM_ID, as in:
SELECT ANIM_ID,
ANIM_NAME,
FOOD_ITEM_ID,
FOOD_ITEM_DESCRIPTION,
FOOD_CATEGORY_DESCRIPTION,
FOOD_PRICE
FROM ANIMAL
INNER JOIN ANIMAL_DIETARY_REQUIREMENTS
USING (ANIM_ID)
INNER JOIN FOOD_ITEM
USING (FOOD_ITEM_ID)
INNER JOIN FOOD_CATEGORY
USING (FOOD_CATEGORY_ID)
INNER JOIN FOOD_ITEM_SUPPLIER
USING (FOOD_ITEM_ID)
WHERE (ANIM_NAME = 'Brianna' OR
ANIM_NAME = 'Isaiah') AND
(FOOD_ITEM_ID, FOOD_PRICE) IN (SELECT FOOD_ITEM_ID, MIN(FOOD_PRICE)
FROM FOOD_ITEM_SUPPLIER
GROUP BY FOOD_ITEM_ID);
You could also replace the OR'd animal name selections with
ANIM_NAME IN ('Brianna', 'Isaiah')
which would be shorter and eliminate the ambiguity without parentheses.

Answer 2

It's suitable you use parentheses around your OR statement to be isolated, and include FOOD_ITEM_ID with FOOD_PRICE for comparison of MINIMIUM prices in the WHERE clause:
WHERE (ANIM_NAME = 'Brianna' OR ANIM_NAME = 'Isaiah')
AND (FOOD_ITEM_ID,FOOD_PRICE) IN
(SELECT FOOD_ITEM_ID,MIN(FOOD_PRICE)
FROM FOOD_ITEM_SUPPLIER
GROUP BY FOOD_ITEM_ID);