如何在rails活动记录查询中比较null

Question

如何在rails活动记录中匹配null.

User.where(['id = ? and active = ? and activation_code = ?', params[:id], 0, NULL]).first

要么

 User.where(['id = ? and active = ? and activation_code = ?', params[:id], 0, nil]).first

两者都不起作用.

Answer 1

诀窍是使用散列,在这种情况下,ActiveRecord将使用"IS NULL"正确生成nil值的SQL.

User.where({:id => params[:id], :active => 0, :activation_code => nil})

Answer 2

试试这样:

User.where(['id = ? and active = ? and activation_code IS NULL', params[:id], 0]).first

Answer 3

在Rails 4中,您可以这样做:

User.where(id: params[:id], active: 0).where.not(activation_code: nil)