How to retrieve data from json string and put it into table columns separately

Hello, need an experts advice on how to alter read data function to retrieve data in json encoded string and put them in the table list;
For now i have Read data function read_submissions and View function submissions_list with data provider {var:read_submissions}.
The problem is that It can read all the data needed except that of json string:
{"1":{"dal_uzv":"Janis","dal_vards":"Berzins","dal_kods":"00101010","dal_epasts":"email@email.com"}}
all of this is stored in the column [rep]
I need this to show in table in separate columns.
​
can anyone help me with this?
Thanks!

Try

{var.jsonde:read_submissions.[n].rep}

Which I doubt will work. But either way {var.jsonde:} will jsondecode whatever JSON you give it.

Khm. Where should I try this?

So for each row of your table, one of the columns should have a list of data from the json column? like
​

column1   column2
text here   text1
            text2
            text3

?