连接查询的问题

SELECT DISTINCT t1.StockAppNum,EmpNum,StockAppDate,ROUND(StockAppSum,2) AS StockAppSum,StockAppSign FROM
 StockApply AS t1 INNER JOIN StockApply_Two ON t1.StockAppNum=StockApply_Two.StockAppNum where
  StockAppSign=1 AND StockEndSign=0 AND StockApply_Two.StockAppNum LIKE '%y%'
直接执行没有问题，但使用存储过程后
'SELECT DISTINCT t1.'+@returnFld+' FROM '+@tblName+' AS t1 INNER JOIN '+@linkTblName +' ON t1.'+@fldName +'='+@linkTblName+'.'+@fldName

显示无法绑定由多个部分组成的标识符 "StockApply_Two.StockAppNum"。
 不知道是怎么回事？？