空值位于:conditions =>

Question

 Contract.all(:conditions => ['voided == ?', 0]).size
 => 364
 Contract.all(:conditions => ['voided != ?', 0]).size
 => 8
 Contract.all.size
 => 441

3个数字的总和(364 +8 != 441)。编写:conditions来计算voided列值为NULL或等于零的行的正确方式是什么？

Answer 1

 Contract.all(:conditions => ["voided is ?", nil]).size

 Contract.all(:conditions => ["voided is not ?", nil]).size

Answer 2

Contract.all(:conditions => {:voided => nil})

或

Contract.all(:conditions => ['voided IS NULL'])