I have a saved search with a criteria to compare two datetime fields ("Is field A after field B?"). The only way I know to do this is to use date arithmetic with a Formula(numeric) criteria, something like this:

{custrecord_plp_project_id.lastmodified} - {custentity_nv_projorpricinglastupdated}

Unexpected Error

to_date(to_char({custrecord_plp_project_id.lastmodified}, 'mm/dd/yyyy hh24:mi:ss'), 'mm/dd/yyyy hh24:mi:ss') -  to_date(to_char({custentity_nv_projorpricinglastupdated}, 'mm/dd/yyyy hh24:mi:ss'), 'mm/dd/yyyy hh24:mi:ss')