3. The method according to claim 2 , wherein the performing no operation of an execution stage of the second query plan using the sort merge join on records already subjected to the nested loop join operation of the first query plan in the driving table of the first query plan comprises: sorting the driving table according to the join column after removing the records already subjected to the nested loop join operation of the first query plan, to obtain a sorted table of a remaining driving table; and performing a merge join operation on the sorted table of the remaining driving table and the sorted table of the other table to obtain the remaining query results.
2. A method of database query, comprising: in response to a query request, obtaining a first query plan for minimum query, response time and a second query plan for minimum query total time for the query request; starting execution of the first query plan and execution of the second query plan at substantially a same time; outputting, before execution of the second query plan reaches a specified point, an initial query result obtained from execution of the first query plan; and in response to execution of the second query plan reaching the specified point, continuing execution of the second query plan to output remaining query results, wherein the first query plan is a query plan using a nested loop join operation, the second query plan is a query plan using a sort merge and the specified point is a point where a construction stage of the sort merge loin operation ends, wherein in the construction stage of the sort merge join operation, another table which is not a driving table of the first query plan is sorted according to a join column to obtain a sorted table of the another table, and wherein continuing execution of the second query plan comprises: performing no operation of an execution stage of the second query plan using the sort merge join on records already subjected to the nested loop join operation of the first query plan in the driving table of the first query plan.