Rails Error :Column 'id' in order clause is ambiguous

错误Column 'id' in order clause is ambiguous 易出现在

p = Product.find(:all,:include=>:kind,:order=>"id desc")

类似的语句上,用include包含了一个left join对象,所以id可能存在于多个表内,就引起了二义性
修改为

p = Product.find(:all,:include=>:kind,:order=>"products.id desc")

属性前加上表名
一切OK