Queries :: Join Fields Query

I tried doing a search but couldnt find the i needed.

Category_name Sku
cars 1
Trucks 1
Bikes 1
Phones 2
Tablets 2
Hats 3

and what i need to is something that will link all sku 1 category names in a new field with a | divider and then all the sku 2 category names together with | as a divider and so on. the amount of categories is different for every sku.

so it looks like this

Joined_categories sku
Cars|Trucks|Bikes 1
Phones|Tablets 2
Hats 3

And if this is easy enough, its not that important though but to delete duplicate category names when it transfers them across to a new field joined together.