Hi @Ed22, This is possible. How this should be achieved depends a little if the CF's are read only or persistent fields.

What you could do is create a NEW custom attribute which has an expression like (v.CF$_12 - v.CF$_11). 

One is read only and one is persistent field.

So, if I have attribute name1: “CF_NPRISPEVOK_K_ZISKU” and attribute name2: “CF_AAA_CISLO”, I should create Read Only Field, which will have Expression Statement: “v.CF$_NPRISPEVOK_K_ZISKU - v.CF$_AAA_CISLO”? Because this is not working

@Ed22 

Arguments : v.CF$_NPRISPEVOK_K_ZISKU, v.CF$_AAA_CISLO

Statement :

SELECT :CF$_NPRISPEVOK_K_ZISKU - :CF$_AAA_CISLO

from dual

it says that “The column CF$_NPRISPEVOK_K_ZISKU refered to in table t is not an approved persistent Custom Attribute. CF$_NPRISPEVOK_K_ZISKU”

you can’t call any CF from the standard IFS table, but the view.

That’s why it’s important to make the difference in between t for Table and v for View when you list your arguments

Question : only consider the v.OBJKEY as argument

and do something like 

SELECT CF$_NPRISPEVOK_K_ZISKU - CF$_AAA_CISLO

from your_ifs_view

where OBJKEY = :OBJKEY

CF$_AAA_CISLO belongs to SALES_PRICE_LIST_PART_PRICE view, but CF$_NPRISPEVOK_K_ZISKU is persistent field and dont belong to any view.

This is my SQL statement: 

“SELECT CF$_NPRISPEVOK_K_ZISKU - CF$_AAA_CISLO
from SALES_PRICE_LIST_PART_PRICE
where OBJKEY = :OBJKEY”

Arguments: “v.OBJKEY” 

it says: “There might be a problem with the select statement. No further validation can be made for a Read Only Select Field before publishing” 

but CF$_NPRISPEVOK_K_ZISKU is persistent field and dont belong to any view

I don’t understand what you mean, a custom field must be attached to a view and must be published AND approved to be called in your case, so CF$_NPRISPEVOK_K_ZISKU

I am not sure about this task, but I think that in  CF$_NPRISPEVOK_K_ZISKU they are inputing values manually, and CF$_AAA_CISLO is located in SQL view SALES_PRICE_LIST_PART_PRICE

for example, in view is default value for column CF$_AAA_CISLO = 64,11and they manually input value for persistent field in CF$_NPRISPEVOK_K_ZISKU = 68,76 and I want the difference

Just noticed an error in your sql querry :

“SELECT CF$_NPRISPEVOK_K_ZISKU - CF$_AAA_CISLO
from SALES_PRICE_LIST_PART_PRICE
where OBJKEY = :OBJKEY”

the SALES_PRICE_LIST_PART_PRICE view can’t reach any CF, but SALES_PRICE_LIST_PART_PRICE_CFV

one is read only and is located in SQL and second one is persistent field which is not located in any SQL. I tried to make difference: This is inputed in expression (CF$_NPRISPEVOK_K_ZISKU - CF$_AAA_CISLO) but in final tab it returns nothing. 

I know how to make difference between two columns which are located in SQL, but I am not sure if it is possible if one is readonly and other one persistent field.