System.QueryException: List has no rows for assignment to SObject

Question

following apex code

public String getLastUpdatedAt() {
String timeStr;
DatadoctorStatus__c last = [SELECT LastUpdated__c FROM DatadoctorStatus__c ORDER BY LastUpdated__c DESC LIMIT 1];
if (last == null){
    timeStr = 'Not yet updated.'; 
} else {
DateTime d = datetime.now();
    timeStr = d.format('MMMMM dd, yyyy hh:mm a z');
} 
return timeStr;
}

is giving me System.QueryException: List has no rows for assignment to SObject if there are no (zero) rows in DatadoctorStatus__c SObject.

Answer 1

Change your query to:

List<DatadoctorStatus__c> last = [SELECT LastUpdated__c FROM DatadoctorStatus__c ORDER BY LastUpdated__c DESC LIMIT 1];
if (last.isEmpty()){
        timeStr = 'Not yet updated.'; 
} else {
        DateTime d = datetime.now();
        timeStr = d.format('MMMMM dd, yyyy hh:mm a z');
} 

Answer 2

Get the response in a list and then further do you manipulations.

List<DatadoctorStatus__c> last = [SELECT LastUpdated__c FROM DatadoctorStatus__c ORDER BY LastUpdated__c DESC LIMIT 1];
if (last.size() == 0){
        timeStr = 'Not yet updated.'; 
} else {
        DateTime d = datetime.now();
        timeStr = d.format('MMMMM dd, yyyy hh:mm a z');
} 

You can also use last.isEmpty() function instead of last.size() == 0. isEmpty() Returns true if the list has zero elements.

Answer 3

It works as expected.You can do 2 things 1) wrap the query in a try catch block

try{ query} catch(exception ex){}

2) make the last as a list than havng it as an instance of datadoctorstatus_c then do for(datadoctorstatus_c l: last) { if(l== null){} }