group_concat Query w/ Generated Nulls

[n/a n/a]

Hello,

I am trying to generate a query that produces an array in the form of a delimited group_concat with the caveat that it is populated with NULL or empty sets when there isn't a matching combination in the lookup table.

I would add that I am not the database administrator so I am limited in terms of schema/table setups and the integrity of the data I am querying. I have provided a visual example below of what I am looking for.

I am a bit rusty on my MySQL, but I have been explored quite a few places on the web without finding quite what I am looking for, and it is difficult to express my need in a very searchable phrase. Any help is certainly appreciated:

Table 1:

PID | Category
-------------
1 | Chairs
2 | Hats
3 | Appliances

Table 2:

FID | Location
--------------
1 | 1
1 | 2
2 | 1
2 | 5
3 | 1
3 | 2
3 | 3
3 | 4
3 | 5

Desired Output From Query:

Category | group_concat(Location)
---------------------------------
Hats | 1,NULL,NULL,NULL,5

or

Category | group_concat(Location)
---------------------------------
Hats | 1,,,,5