1  1 select * from TblProduct
 2  2 where (@proName=‘‘ or chvProName like ‘%‘+@proName+‘%‘)
 3  3 and (@minPrice=‘‘  or mnyProPrice>=@minPrice)
 4  4 and (@maxPrice=‘‘ or mnyProPrice<=@maxPrice);
 5  5 
 6  6--下面将参数替换成字符串
 7  7 --测试
 8  8 select * from TblProduct
 9  9 where (‘‘=‘‘ or chvProName like ‘%‘+‘‘+‘%‘)
10 10 and (‘‘=‘‘  or mnyProPrice>=null)
11 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<=‘‘);