Is_in_1month2__c false IF(ISBLANK(Contract_recognized_day_1__c) && NOT(ISBLANK(Day_Update__c)), true, YEAR(Contract_recognized_day_1__c) = YEAR(Evaluation_date__c) && MONTH(Contract_recognized_day_1__c) = MONTH(Evaluation_date__c) ) BlankAsZero false false Checkbox