how to write special subselection

[qipenglin]

I have a business scenarios to calculate the sum of each account's latest snapshot's amount, the sql is "SELECT SUM(amount) AS total_amount FROM account_snapshot AS t1 WHERE create_time = (SELECT MAX(create_time) FROM account_snapshot AS t2 WHERE t1.account_id = t2.account_id)" ，how to write the code with MPJLambdaWrapper？（assume that the model class is AccountSnapshot and it has three fileds named with accountId, createTime, amount）.