Advanced search using php/mysql?

currently I am working on an online shop using PHP and Mysql.

this online shop will have an advanced search function.

the search function will include stuff like SIZE and COLOR.

I store the products in the products table in mysql database which looks like this:

id   product_name   price    category
3      shirt         29       clothes
4      shoes         19       clothes

and I have two separate tables in mysql database for COLORS and SIZES and I use the for each loop to insert the data into those two tables for each selected size/color!

so they look like this:

color's table:

idc    id   product_name    color  
 1      3      shirt         red       
 2      3      shirt         white
 3      3      shirt         black 
 4      3      shirt         pink 
 5      4      shoes         black 
 6      4      shoes         brown 

sizes table:

idc    id   product_name    size  
 1      3      shirt         small      
 2      3      shirt         large
 3      4      shoes         5 
 4      4      shoes         6 

the column id is identical in all the tables.

now, I have some simple checkboxes in my php search page which i want to allow users to click on search by size/color etc etc.

the check boxes look like this:

<input type="checkbox" name"size[]"  value"small"/>
<input type="checkbox" name"size[]"  value"large"/>
<input type="checkbox" name"size[]"  value"xlarge"/>
<input type="checkbox" name"size[]"  value"xxlarge"/>
<input type="checkbox" name"size[]"  value"6"/>
<input type="checkbox" name"size[]"  value"7"/>
<input type="checkbox" name"size[]"  value"8"/>
<input type="checkbox" name"size[]"  value"9"/>

<input type="checkbox" name"colors[]"  value"red"/>
<input type="checkbox" name"colors[]"  value"white"/>
<input type="checkbox" name"colors[]"  value"black"/>
<input type="checkbox" name"colors[]"  value"brown"/>

the issue that I have is that I cannot come up with any solution (code) for this advanced search!

question that I have:

1- am I approaching this correctly by separating size, colors and products in different tables in mysql database?

2- if the answer to the above is yes, is using the following code correct:

SELECT
  products.id,
  products.product_name,
  products.price,
  products.category,
FROM products
INNER JOIN colors ON products.id= colors.id
INNER JOIN sizes ON products.id= sizes.id
WHERE (
     sizes.size LIKE '%whatever%' OR
     colors.color LIKE '%whatever%'
      ) 

any help and advise would be greatly appreciated.

Thanks in advance.