I want buy a camera

I want buy a single-lens reflex camera. Recently I taken a lot of photos using smart phone. The phone camera is easy to use and also could take high resolution photos. But the resolution is not good enough to see when I expend the photo. So I want have a single-lens reflex camera. It can take really high resolution photos. I told my idea to my wife, she agreed. Then I am thinking when going to camera shop.