Marie works for a busy pediatrician's office. The practice has a sophisticated database for all records and information that pertain to the practice. The doctor for whom she works is participating in an academic study, and she needs a report that lists the patient's name, date of birth, and the names of parents or guardians. The doctor would like to see the patient's full name in the format Lastname, Firstname even though they are separate fields in the database. She would also like to see the data for the fields Mother, Father, and Guardian, regardless of whether or not data is actually entered in those fields. Based on the doctor's requirements for the report, Marie must create a query on which to base the report.
Because the doctor wants all data entered for parents and guardians regardless of the data in the field, Marie must create a calculated field in the query with a function that tests the Mother, Father, and Guardian fields for a condition that is either true or false. If the condition is true, one result will be displayed, and if the condition is false a different result will be displayed. Which function should Marie use for this calculated field?