How to check for presence of 'key' in jq before iterating over the values

I get Cannot iterate over null (null) from the below query because .property_history is not present in result object.

How do I check for the presence of .property_history key before proceeding with map(...)?

I tried using something like

sold_year= `echo "$content" | jq 'if has("property_history") then map(select(.event_name == "Sold"))[0].date' else null end

Original Query:

sold_year=`echo "$content" | jq '.result.property_history | map(select(.event_name == "Sold"))[0].date'`

JSON:

{"result":{"property_history":[            {"date":"01/27/2016","price_changed":0,"price":899750,"event_name":"Listed","sqft":0            },            {"date":"12/15/2015","price_changed":0,"price":899750,"event_name":"Listed","sqft":2357            },            {"date":"08/30/2004","price_changed":0,"price":739000,"event_name":"Sold","sqft":2357            }        ]    }}