need advice on mysql data base design

Question

I need to build application where users can search/filter products by multiple characteristics. There are 25 product groups. Each product group have around 10 product characteristics. I have a few data base design solutions, but none of them seems appropriate enough:

1. Create 25 tables per each group with column names storing product group characteristics.
2. Create one table with all products and as many columns as there are product characteristics (~ 200)
3. EAV: create 1 table for all characteristics and 1 table with all products and their attributes stored in rows, not in column names. This solution will result in writing a lot of application code, because I won't be able to select a product with all characteristics in one row. I will have to write application code to group mysql results.

I believe there are already solutions for problems like mine. Thanks for help.

EDIT:

In most cases the characteristics in groups are entirely different. These are starter/alternator components. Only around 25% of characteristics can overlap, like physical characteristics, length, diameter, etc.

Answer 1

I would suggest the following: Create 3 tables; Groups, GroupCharacteristics,Products.

1. Groups is linked to both tables.
2. GroupCharacteristics will have the list of characteristics, using 3 columns, (1)GroupName,(2)CharacteristicName,(3)Mapping [Values for mapping could be C01,C02 through C10] You will use mapping later on. One group has many characteristics so it's a one to many link.
3. Products will have 12 Columns; (1)ProductName/Id,(2)GroupName,(3)C01,(4)C02 ... (12)C10. The C** columns will be filled with the values of the related characteristics in order to keep them mapped correctly.

Groups:
[GroupName]
1-Vehicles
2-Furniture
Characteristics:
[Map][Group][Characteristic]
1-C01 | Vehicles | Length
2-C02 | Vehicles | Volume
3-C03 | Vehicles | Type
4-C01 | Furniture | Height
5-C02 | Furniture | Volume
6-C03 | Furniture | Length
Products:
[ProdName][Group][C01][C02][C03]...
1-Car | Vehicles | 2 | 50 | Hatchback
2-Jet | Vehicles | 10 | 70 | Null
3-Table| Furniture | 1 | null | 1.6
4-Cup | Furniture |0.1 | 0.12 | null

String col = Select Map from Characteristics where Group = 'Vehicles' and Characteristic = ' Type'
-- this returns the column (in this case C03) then --
String sql = "Select ProdName from Products where Group = 'Vehicles' and "+col+"='Hatchback'"
-- this will build the query in a string then you just execute it --
execute(sql)
-- in whatever language you're using this is just the basic idea behind the code you have to write.