1. what are the rules for splitting the field?
2. what is the code the does #1?
3. how does one return four different fields in a query using a splitter function as is implied by #1,#2?

1. only you know the rules

2. we don't normally write code for people, only point them in the right direction, though if someone wants to provide you some code that is OK

3. there are two easy ways to split one field into multiple columns in a query:
   a. use a function of complex expression called four times, once for each field to be returned
   b. use a user defined object and table types and return same from a table function in order to present the fields as defined by the object types

select a.*,b.*
from sometable a
    ,table(cast(tablefunction(a.somecolumn) as userdefinedtype)) b
/