Storing The Values Of Dynamic Columns In Oracle

I have a requirement to execute the query only once for all the columns mapped to a particular table. Lets take an example..

table t1 has the following columns mapping.

col1 col2 col3 col4
variable 1 table abc col1_abc ----
variable 2 table abc col2_abc ----
variable 3 table xyz col1_xyz ----
variable 4 table xyz col2_xyz ----
variable 5 table xyz col3_xyz ----
variable 6 table xyz col4_xyz ----

In col4 , we have to update the values of col3 (column) ... it is very easy to update the values by executing the query for each column but my requirement is ... I want to execute the query once for a table ( example select col1_abc,col2_abc from table_abc ... this will return always a single value after adding other conditions in where clause) and why I want to do this? .. because there can be multiple (might be 30 variables values)
from a single table.

I have converted the columns into rows by using listagg function now I have lets a dynamic query ( for the above example).

for i in 1.2
loop

l_query := ' select col1_abc, col2_abc from table_abc';
open c1 for l_query;

end loop;

my problem is : how to hold these values and update the above table?