Exporting SQL databases?

Question

MySQL

Due to the fact that the virus patched and changed the system dlls when leaving, Windows began to knock out the blue screen of death and was advised to reinstall. Everything would be fine, but WSL with MySQL databases was raised on Windows 10: one for Postfix; another for Dovecot + Postfix + SASL; the third for hMailServer; the fourth one is for Prosody (XMPP/Jabber). How can I export Databases, so that later I can transfer them to a new OS?!
Tell me please!!!