Select All Fields with SOQL in Apex by Using Record Id

Sample Code:

Id recordId = '00128000002KuXO';

DescribeSObjectResult descResult = recordId.getSObjectType().getDescribe();
List<String> fieldList = new List<String>(descResult.Fields.getMap().keySet());

String query = ' SELECT ' + String.join(fieldList, ',') + ' FROM ' + descResult.getName() + ' WHERE ' + ' id = :recordId';
List<sObject> records = Database.query(query);

System.debug(records);