sql - Column names based on a mapping table on mysql -

i new mysql. have 2 tables.

table 1:product_details

manufacturerid| sku | image1                   | image2                   | image3 --------------------------------------------------------------------------------------------------      123      |  1  | image1-sku1-filename.jpg | image2-sku1-filename.jpg | image3-sku1-filename.jpg          123      |  2  | image1-sku2-filename.jpg | image2-sku2-filename.jpg | image3-sku2-filename.jpg          123      |  3  | image1-sku3-filename.jpg | image2-sku3-filename.jpg | image3-sku3-filename.jpg      456      | 10  | image1-sku10-filename.jpg| image2-sku10-filename.jpg| image3-sku10-filename.jpg      456      | 20  | image1-sku20-filename.jpg| image2-sku20-filename.jpg| image3-sku20-filename.jpg 

table 2:image_mapping

manufacturerid | image_column | image_type -------------------------------------------     123        | image3       | master     123        | image1       |     123        | image2       |     456        | image3       | master 

i need select query maps products (sku) product images (will replace image column names in table 2) per manufacturerid , per sku.

table 3: product_images

manufacturerid | sku | product_image            | image_type --------------------------------------------------------------     123        |  1  | image3-sku1-filename.jpg | master     123        |  1  | image1-sku1-filename.jpg |     123        |  1  | image2-sku1-filename.jpg |     123        |  2  | image3-sku2-filename.jpg | master     123        |  2  | image1-sku2-filename.jpg |     123        |  2  | image2-sku2-filename.jpg |     123        |  3  | image3-sku3-filename.jpg | master     123        |  3  | image1-sku3-filename.jpg |     123        |  3  | image2-sku3-filename.jpg |     456        | 10  | image3-sku10-filename.jpg| master         456        | 20  | image3-sku20-filename.jpg| master 

the following works me data:

select pd.manufacturerid, sku,         case when im.image_column = 'image1' pd.image1              when im.image_column = 'image2' pd.image2             when im.image_column = 'image3' pd.image3              end prod_image, im.image_type product_details pd join image_mapping im on pd.manufacturerid = im.manufacturerid; 

sqlfiddle: http://sqlfiddle.com/#!9/76fc1/3/0