2. The system as recited in claim 1 , wherein the query condition evaluating means performs continuous query on the new data transmitted from the data separating means.
1. A stream data processing system for avoiding duplication of data processing, comprising: an evaluation result storing means for updating and storing a query condition evaluation result; a window evaluating means for performing window evaluation on stream data; a data separating means for separating for stream data transmitted from the window evaluating means into new data and duplication input data based on reusability of the previous query condition evaluation result; a reuse result extracting means for receiving duplication input data from the data separating means and extracting a query condition evaluation result from the evaluation result storing means; a query condition evaluating means for receiving new data from the data separating means, performing query condition evaluation and creating a query condition evaluation result; and a result organizing means for receiving the query condition evaluation results from the reuse result extracting means and the query condition evaluating means, merging, outputting and transmitting the query condition evaluation result to the evaluation result storing means.