1 select * from TblProduct

  2 where (@proName='' or chvProName like '%'+@proName+'%')

  3 and (@minPrice=''  or mnyProPrice>=@minPrice)

  4 and (@maxPrice='' or mnyProPrice<=@maxPrice);

  5

  6--下面将参数替换成字符串

  7 --测试

  8 select * from TblProduct

  9 where (''='' or chvProName like '%'+''+'%')

 10 and (''=''  or mnyProPrice>=null)

 11 and (''='' or mnyProPrice<=null);
--检索出所有的商品

--如果更改成下面代码：会报【从数据类型 varchar 转换为 numeric 时出错。】的错

select * from TblProduct

where (' '=' ' or chvProName like '%'+''+'%')

and (' ' is null  or mnyProPrice>='')

and (' ' is null or mnyProPrice<='');