当我运行下面的SQL时，我遇到了以下错误
FuncTwo（ParamOne，ParamTwo）InnedColTwo，*
ORA-06502：PL/SQL：数值或值错误：数字精度太大ORA-06512：在“Schema.FuncTwo”，第89行

SELECT 
    C.UID AS ColOne,
    TO_NUMBER(C.ColTwo) AS ColTwo
FROM (
        SELECT
            B.UID,
            TO_NUMBER(B.MiddleColTwo) AS OuterColTwo
        FROM (
                SELECT 
                    A.UID,
                    CASE
                        WHEN (InnerColThree >= '54.6' AND InnerColThree <= '54.9') OR InnerColThree = '0' THEN 99
                        ELSE TO_NUMBER(InnerColTwo, '99.9')
                    END AS MiddleColTwo
                FROM (
                        SELECT 
                            UID,
                            FuncTwo(ParamOne, ParamTwo) InnerColTwo,
                            FuncThree(ParamOne, ParamTwo) InnerColThree
                        FROM
                            -- SOME STUFF
                        WHERE
                            -- SOME STUFF
                        UNION
                            SELECT 
                                UID,
                                FuncTwo(ParamOne, ParamTwo) AS InnerColTwo,
                                FuncThree(ParamOne, ParamTwo) AS InnerColThree
                            FROM 
                                -- SOME STUFF ...
                            WHERE 
                                -- SOME STUFF ...
                    ) A
            ) B
        WHERE B.ColTwo > 0 --Works when commented out. Throws error when uncommented.
    ) C;

但是当我注解掉WHERE B.ColTwo > 0时，查询就可以工作了。我尝试用TO_NUMBER（）为所有ColTwo值指定数字格式，但没有任何帮助。
我不明白为什么当中间的查询where子句被注解掉时，查询会解析，但当它被取消注解时，查询会失败。
该列的所有值都解析为0到99之间的值，没有小数或负值或大于99的值。
有人能帮我解决这个问题吗？