Formula Value Creation

Question

Hi All,
I want to create a final value based on the formula created from the table:
STEP
OPERATOR
VARIABLE
VAR_VALUE
1
A
10
2
0
B
20
3
4
C
30
5
D
40
6
7
0
E
50
8
-0
9
F
60
10
G
70
11
The Formula that i am creating is
SELECT LISTAGG(operator || variable)       
       WITHIN GROUP(ORDER BY step) formula
  FROM bharat_formula;
The result is A+B*(C/D)+E-(F*G)
and the formula with value that i am creating is :
SELECT LISTAGG(operator || var_value)
       WITHIN GROUP(ORDER BY step) formula
  FROM bharat_formula;
and the result is 10+20*(30/40)+50-(60*70)
Now i want to formulate the formula as 10+20*(30/40)+50-(60*70) and get the calculated value of the formula as -4125.
Can any body please help me in how to create the formula and calculate the value in a single statement?

Answer 1

May be
SQL> with t
  2  as
  3  (
  4  select 01 step, ''  operator, 'A' variable, 10    var_value from dual union all
  5  select 02 step, '0' operator, 'B' variable, 20    var_value from dual union all
  6  select 03 step, '*' operator, ''  variable, null  var_value from dual union all
  7  select 04 step, '(' operator, 'C' variable, 30    var_value from dual union all
  8  select 05 step, '/' operator, 'D' variable, 40    var_value from dual union all
  9  select 06 step, ')' operator, ''  variable, null  var_value from dual union all
10  select 07 step, '0' operator, 'E' variable, 50    var_value from dual union all
11  select 08 step, '-0'operator, ''  variable, null  var_value from dual union all
12  select 09 step, '(' operator, 'F' variable, 60    var_value from dual union all
13  select 10 step, '*' operator, 'G' variable, 70    var_value from dual union all
14  select 11 step, ')' operator, ''  variable, null  var_value from dual
15  )
16  select replace(sys_connect_by_path(str, ','), ',') formula
17       , xmltype
18         (
19            dbms_xmlgen.getxml
20            (
21               'select ' || replace(sys_connect_by_path(str, ','), ',') ||
22               ' val from dual'
23            )
24         ).extract('/ROWSET/ROW/VAL/text()') val
25    from (
26            select step
27                 , ' '
28                   || decode(operator, null, ' ', '0', '+', '-0', '-', operator)
29                   || ' '
30                   || to_char(var_value) str
31              from t
32         )
33   where connect_by_isleaf = 1
34   start with step = 1
35  connect by step = prior step + 1;
FORMULA                                            VAL
   10 + 20 *  ( 30 / 40 )  + 50 -  ( 60 * 70 )     -4125
SQL>