Sampling analysis includes classifying a plurality of query keywords into a plurality of query keyword subsets according to page view (PV) values associated with the plurality of query keywords, the plurality of query keywords being submitted by a plurality of users; determining a respective plurality of sample rates of a respective plurality of query keywords in a respective one of the plurality of query keyword subsets; and sampling query data in the respective one of the plurality of query keyword subsets according to the respective plurality of sample rates.