PL/SQL 实现基本的四则运算

CREATE OR REPLACE PACKAGE BODY PACK_RISK_FUNCTION AS
--- 1 将符号替换成#号 或许可以用正则表达式，但是嫌麻烦还是直接用替换
FUNCTION CHANGE_OPERATOR(FORMULA VARCHAR2)
RETURN VARCHAR2
AS
V_FORMULA VARCHAR2(100);
BEGIN
V_FORMULA := REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(FORMULA,'(',''),')',''),'+','#'),'-','#'),'*','#'),'/','#');
RETURN V_FORMULA;
END CHANGE_OPERATOR;
/**---- 2 将字符串按照 # 解析成不同字段**/
---- 创建一个TABLE变量 CREATE OR REPLACE TYPE STR_SPLIT IS TABLE OF VARCHAR2 (4000);
---- 调用函数语句 SELECT * from TABLE(SUB_FORMULA(FORMULA))
FUNCTION SUB_FORMULA(FORMULA VARCHAR2)
RETURN STR_SPLIT PIPELINED
AS
V_LENGTH NUMBER :=LENGTH(FORMULA);----字符串长度
V_INDEX NUMBER; ---- #的位置
V_START NUMBER:=1; ---开始位置
BEGIN
WHILE V_START <= V_LENGTH LOOP
V_INDEX:= INSTR(FORMULA,'#',V_START);
IF V_INDEX =0 THEN
PIPE ROW(SUBSTR(FORMULA,V_START));
V_START :=V_LENGTH + 1;
ELSE
PIPE ROW(SUBSTR(FORMULA,V_START,V_INDEX-V_START));
V_START := V_INDEX + 1;
END IF;
END LOOP;
RETURN;
EXCEPTION
WHEN OTHERS THEN
DBMS_OUTPUT.PUT_LINE(SQLCODE || ' ' || SQLERRM);
RETURN;
END SUB_FORMULA;
/**
---3 四则运算函数**/
FUNCTION OPERATION_GLOBAL (FORMULA IN RISKITEMINFO.RECKONNAME%TYPE)
RETURN VARCHAR2
IS
FORMULA_V RISKITEMINFO.RECKONNAME%TYPE :='('||FORMULA||')';
V_FORMULA VARCHAR2(500); ------储存转成#号后的公式
FIELD_NO VARCHAR2(100); ------字段编号
FIELD_VALUE VARCHAR2(100); --- 数据值
FIELD_TYPE NUMBER(2); ---- 数据类型
RESULT_V NUMBER;
/* V_COUNT NUMBER;*/
R_RESULT VARCHAR2(100);
BEGIN
------ 调用CHANGE_OPERATOR函数，将四则运算符号转换成#
V_FORMULA :=PACK_RISK_FUNCTION.CHANGE_OPERATOR(FORMULA);
-----创建游标C1_CURSOR 用于保存 公式分割后的字段名
DECLARE
CURSOR C1_CURSOR IS
SELECT * from TABLE(PACK_RISK_FUNCTION.SUB_FORMULA(V_FORMULA));
BEGIN
OPEN C1_CURSOR;
FETCH C1_CURSOR INTO FIELD_NO;
WHILE C1_CURSOR%FOUND LOOP
-----根据字段名查找最后日期的数据进行计算
   SELECT A.FIELDTYPE,B.FIELDVALUE INTO FIE