We added a repeater group to the comment form: namely 2 fields:
Now we need to sum up all the numbers of the same Material. (so; spread all over the comments)
Thing is: repeater fields have different meta_keys; like material_0 and material_1.
Also for the number; number_0 and number_1.
So, it’s hard to extract data.
Advice is very welcome. Stuck here :-<