MYySQL is the Table Relationship wrong? - mysql

Question

I'm very new in Databases and more specific in MYSQL. I use xampp + MySQL Workbench.
I make 3 tables using MySQL Workbench:
- tbStores with fields StoreID(PK-INT-AI), StoreName
- tbProducts with fields ProductID(PK-INT-AI), ProductName
- tbProductDetails with fields ProductDetailID(PK-INT-AI), Price, ProductID(FK), StoreID(FK)
*PK=Primary Key
*INT=Numeric Type Attributes
*AI=Auto Increments
In case you don’t understand the Relationships above:
1 to many From tbStores(StoreID) To tbProductDetails (StoreID)
1 to many From tbProducts(ProductID) To tbProductDetails (ProductID)
I add values to the fields:
- tbStores=> StoreName=> Store 1
- tbProducts=> ProductName=> Product 1, Product 2
- tbProductDetails=> Price=> 50, 30
- tbProductDetails=> ProductID=> 1, 2
- tbProductDetails=> StoreID=> 1, 1
To the Query:
SELECT tbStores.StoreName, tbProductDetails.Price, tbProducts.ProductName
FROM tbStores, tbProductDetails, tbProducts
Where ProductName = 'Product 1';
The Problem:
Query will return this
Store 1, 50, Product 1
Store 1, 30, Product 1
Is giving me Same Product with 2 different Prices.
What I was expecting to take was this :
Store 1, 50, Product 1
What am I doing wrong? I believe it has to do with relationships but I can't figure it out. Thanks

Answer 1

You need to join the tables together (specify how they are related) in the query, the query should look something like this:
SELECT tbStores.StoreName, tbProductDetails.Price, tbProducts.ProductName
FROM tbProductDetails
JOIN tbStores ON tbStores.StoreID = tbProductDetails.StoreID
JOIN tbProducts ON tbProducts.ProductID = tbProductDetails.ProductID
WHERE tbProducts.ProductName = 'Product 1';
If you want all products you have to remove the where clause. Note that I took the liberty of changing your implicit joins in the from clause to explicit joins using the join keyword.
Sample SQL Fiddle
Sample output:
| STORENAME | PRICE | PRODUCTNAME |
|-----------|-------|-------------|
| Store1 | 50 | Product1 |

Answer 2

What you want is to use JOIN combined with ON
SELECT StoreName, Price, Product Name
FROM tblStores
JOIN tblProduct ON tblStores.StoreID = tblProducts.StoreID
JOIN tblProductDetails ON tblProduct.ProductID = tblProductDetails.ProductID
WHERE ProductName = 'Product 1'
You may consider GROUP BY to identify the specific stores.