How to evaluate an expression in one table field into another?

Question

I have a table, inside there is a field called x, the x field contain value of '1+2', '1+3' etc, how to get these value and calculate it and save into another field?

Answer 1

If the case you have mentioned needs to be considered then I will suggest you use the following query:

select
  xmlquery('3+4'
     returning content
  ).getNumberVal()
from
dual;

If More operators are involved except division then the aforementioned query will work but if the division operator is also involved then you must have to replace "/" with " div " keyword. Something like the following:

select
  xmlquery(
  replace( '20/5', '/', ' div ')
     returning content
  ).getNumberVal()
from
dual;

Now, you can use it in your update statement or anywhere else.

update tab 
set tab.result_column_name = xmlquery(t.your_expr_column_name
         returning content
      ).getNumberVal()

update tab 
set tab.result_column_name = xmlquery(
      replace( t.your_expr_column_name, '/', ' div ')
         returning content
      ).getNumberVal()

Demo

Cheers!!