A stream data processing computer comprises: a query execution module to receive an input stream of stream data, manage execution order of operators for executing a query, and output an output stream, the operators including static recursive execution modules, a judge operator, and a dynamic recursive execution module; and a memory including a temporal store to store data generated in executing the query. The static recursive execution modules are configured to conduct a recursive number of static recursive execution of the query. The judge operator is configured to determine whether a preset condition is met after the recursive number of static recursive execution of the query. The dynamic recursive execution module is configured, if the preset condition is not met, to continue execution of the query by dynamic recursive execution from a last result of a last module of the static recursive execution modules, based on a dynamic recursive value.