Show a text value instead of row id in an reag-only grid

if your record is related (record relationship) to the table's record that you've shown in the image , then you can choose fields from related record also 
as in this case you can use the field nombre from related record.
and if there is no related record then you can get the table's data from query and you can use index along with wherecontains function to get the work done  

Is the second case (not a related record)

where should i do this query,  in the gridColumn oh the read-only grid?

what would be the expression??

1. you have to query from table (use a!queryEntity) to get the data in interface

2. store that value (data) in a local variable

3. in the grid column try this in value parameter ->  

index(
local!/*data's local variable*/.nombre,
wherecontains(fv!row[/*your int record field*/],local!/*data's local variable*/.id),
{}
)

1. you have to query from table (use a!queryEntity) to get the data in interface

2. store that value (data) in a local variable

3. in the grid column try this in value parameter ->  

index(
local!/*data's local variable*/.nombre,
wherecontains(fv!row[/*your int record field*/],local!/*data's local variable*/.id),
{}
)