Qt Program Hangs (Not Responding) Until Function ends then starts working again

Question

I have a UI application in Qt, i have a couple of functions that run large scale SQL queries that returns thousands of results.

when the button that runs this query is clicked the UI windows just instantly goes to 'not responding' however i can see from console outputs that everything is still actually running in the background. As soon as the function ends the data is presented as expected and the UI is responding again and fully functional.

i know this is due to the fact that the function is looping thousands of times due to the large number of results, but i was hoping that i could have just put in a loading bar that progresses as the search does instead of just locking up the window making it look like the program has crashed. AFAIK i dont have memory leaks so does anyone have any suggestions?

oh also im thinking its not memory leaks because when i click that button task manager shows only a couple of MB of memory being used for this process and processor is by no means maxing out either