How can we upsert a list of lists of accounts

Question

I want to update list of list of account. I am getting list of accounts from many sources, now i want to update them.

list<list<sObject>> la=new list<list<sObject>>();
la.add(accountList1);
la.add(accountList2);
upsert la;

Its throwing an error, is there any way through which we can upsert list of list of accounts?

Answer 1

You should instead look at the addAll method, which would allow you to use just one List<Account>:

List<Account> allRecords = new List<Account>();
allRecords.addAll(accountList1);
allRecords.addAll(accountList2);
upsert allRecords;

---

If, for some reason, you really want to maintain separate lists, you will have to flatten the structure you have in your OP:

List<Account> allRecords = new List<Account>();
for (List<Account> accountList : listOfLists)
    allRecords.addAll(accountList);
upsert allRecords;

Answer 2

You can't do this. You can only DML on single records or lists. Instead, make a single list and use addAll:

Account[] records = new Account[0];
records.addAll(accountList1);
records.addAll(accountList2);
upsert records;

As a side note, you also can't upsert on a generic list of SObject, so you'll need to use the Account concrete type instead.