win7下 已经安装了mysql 5.7；现在想安装xampp，需要卸载 mysql吗？

Answer 1

Of course not necessary, but be careful not to conflict with the ports.
If I were you I would uninstall it. Since XAMPP provides a collection package, then use the one in XAMPP (provided you have no requirements on the version).

Answer 2

No need, if you installed it locally, use the local one, just turn off mysql in XAMPP