In the top righthand corner of the query builder, there are two feature buttons: "Autorun" and "Reset".
The Reset button clears the existing query and starts a new one in the same tool. If you are finished with an analysis and would like to build a new one, use the reset button in the top right corner of the query builder to reset the builder.
When selected, the Autorun feature automatically executes your query as changes are made to it. Turning Autorun off allows you to make multiple changes before executing the new query. This can speed up the query building process if you are making many query changes using large data sets.