函数结果作为判断条件-错误ORA-00904,invalid identifier

[junon]

SELECT MATNOCNAME,MOD(to_number(substr(b.matnocid,3)),10) matc,b.matnocid, 
a.viewno ,a.matname ,a.quantity ,a.level1  level2,a.pviewno ,GETMATLINEBYMATID1(a.MATID,'生产') 
 mLuxian,  GETMATLINEBYMATID1(a.MATID,'包装')  ZLuxian 
 from 
 qd2_xqpdmdataparsexuqiunew a ,
 gjy_icmatno_matname b ,
 gjy_icmatnocategory c where 
 instr(ZLuxian,decode(b.matname,'',ZLuxian,b.matname) )>0 AND 
 instr(mLuxian,decode(b.matno,'',mLuxian,b.matno) )>0  
 AND B.MATNOCID=C.MATNOCID  ORDER BY MATNOCNAME ,A.viewno

执行的时候返回

ORA-00904:  "MLUXIAN" invalid identifier

我把mLuxian设置为大写也不行。mLuxian返回的是一个varchar2，可能为空


望各位大侠解惑！谢谢

[真的不知道取什么名]

SELECT MATNOCNAME,MOD(to_number(substr(b.matnocid,3)),10) matc,b.matnocid, 
a.viewno ,a.matname ,a.quantity ,a.level1  level2,a.pviewno ,GETMATLINEBYMATID1(a.MATID,'生产') 
 mLuxian,  GETMATLINEBYMATID1(a.MATID,'包装')  ZLuxian 
 from 
 qd2_xqpdmdataparsexuqiunew a ,
 gjy_icmatno_matname b ,
 gjy_icmatnocategory c 
where 
 instr(GETMATLINEBYMATID1(a.MATID,'生产'),decode(b.matname,'',GETMATLINEBYMATID1(a.MATID,'生产'),b.matname) )>0 AND 
 instr(GETMATLINEBYMATID1(a.MATID,'包装'),decode(b.matno,'',GETMATLINEBYMATID1(a.MATID,'包装'),b.matno) )>0  
--不允许用别名
 AND B.MATNOCID=C.MATNOCID  
ORDER BY MATNOCNAME ,A.viewno

[junon]

那这样子性能不是大打折扣
相同的东西被执行了三次啊

[junon]

不知道Oracle自己会优化不

[真的不知道取什么名]

[Quote=引用 3 楼 junon 的回复:]
不知道Oracle自己会优化不
[/Quote]放心，它不会那么笨的

[junon]

[Quote=引用 4 楼 zhuomingwang 的回复:]

引用 3 楼 junon 的回复:
不知道Oracle自己会优化不
放心，它不会那么笨的
[/Quote]
有道理