I have a class in parse-server which has 20 columns. 6 of these columns has values but others not so in query result just these 6 value comes. Is there any way to retrieve other 14 values ? I just need keys of these 14 values
Query results will only have fields that are set for the object, so no, you cannot get all of the available fields by querying for objects. If you want all of the fields, you'll need to query the schema:
const schema = new Parse.Schema('_User');
const result = await schema.get();
console.log(Object.keys(result.fields));