Great input @ASharp-J
I was thinking about a similar solution but was hesitating, because it is dependent to the length of the string (and you might have different values with different (unknown) length…
But you pushed me rethinking it, and I came up with his solution (I actually used a similar technique before 
)
@Richard-SNN
What do you think about searching for a comma? (only make sure, to have no comma in the values 
)
Update:
using TOTEXT(…) is more secure, because you can search for "," then (a simple comma in the value is no longer an issue)
Context for the update:
TOTEXT(@Table Aggregation.Aggr_Test) output is like so:
["j4gmt7PjnBu23s5R7","cjAMazfQowczQNMEsmx589fTgtoSu2RQjk"]
while @Table Aggregation.Aggr_Test + '' outputs something like this:
j4gmt7PjnBu23s5R7,cjAMazfQowczQNMEsmx589fTgtoSu2RQjk