There are two list collection, a collection is a primary key listA, a set is the name of the table by, these tables are some of the same field, the basis of a primary key in a table won't appear in the other table, going through these primary keys are now query the corresponding records, then in descending order by creating time, by the table in the number of records many thousands to tens of thousands of; Tell you the friend, what is the performance and speed is better way?