Interpreting a field in an equation

Question

I need to use a value from a field as an operator in an equation.
Example: the field holds values like '<' or '>'
in the select statement I want to compare two values using this operator
something like
table.value1 > table.value2
How do I replace the symbol with a field name?

Answer 1

Here is an example.
SQL> SELECT * FROM TEST;
    VALUE1 O     VALUE2
         1 <          0
         2 >          1
         3 <          4
         5 =          5
SQL> DESC TEST
Name                                                  Null?    Type
VALUE1                                                         NUMBER
OPERATOR                                                       VARCHAR2(1)
VALUE2                                                         NUMBER
  1   DECLARE
  2   CURSOR C1 IS
  3   SELECT DISTINCT OPERATOR FROM TEST;
  4   SQLSTMT  VARCHAR2(200) := NULL;
  5   TYPE TESTTAB  IS TABLE OF TEST%ROWTYPE INDEX BY BINARY_INTEGER;
  6   TESTREC TESTTAB;
  7   BEGIN
  8   FOR C1_REC IN C1 LOOP
  9   SQLSTMT := 'SELECT * FROM TEST WHERE TEST.VALUE1 '||C1_REC.OPERATOR||
10              ' TEST.VALUE2 AND OPERATOR = :OPERATOR';
11   EXECUTE IMMEDIATE SQLSTMT BULK COLLECT INTO TESTREC USING C1_REC.OPERATOR;
12   DBMS_OUTPUT.PUT_LINE('SQLSTMT IS: '||SQLSTMT);
13   FOR i in 1..TESTREC.COUNT LOOP
14      DBMS_OUTPUT.PUT_LINE('CASE '||TO_NUMBER(i)|| ': '||TO_NUMBER(TESTREC(i).VALUE1)
15                          || TESTREC(i).OPERATOR||
16                        TO_NUMBER(TESTREC(i).VALUE2));
17   END LOOP;
18   END LOOP;
19*  END;
SQL> /
SQLSTMT IS: SELECT * FROM TEST WHERE TEST.VALUE1 < TEST.VALUE2 AND OPERATOR = :OPERATOR
CASE 1: 3<4
SQLSTMT IS: SELECT * FROM TEST WHERE TEST.VALUE1 = TEST.VALUE2 AND OPERATOR = :OPERATOR
CASE 1: 5=5
SQLSTMT IS: SELECT * FROM TEST WHERE TEST.VALUE1 > TEST.VALUE2 AND OPERATOR = :OPERATOR
CASE 1: 2>1