Use PHP to import mysql data to an XML file.

I want to use PHP to import mysql data to an XML file. I want to use PHP to import the data in the table: floor in mysql to a specified test. XML file. I have found some methods on the Internet that do not work well. I hope some of my friends who have done so will give me the source code ., Reference: this is probably the case, but I just don't know how to import Mysql data into an XML file using PHP.
I want to use PHP to import the data in the table: floor in mysql to a specified test. XML file. I have found some ways on the Internet that are not doing well. I hope some friends who have done so will give me the source code.
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Reference:

This is probably the case, but I just don't know how to output the Mysql database in this XML file.

So you always want to query. Should you save the query results to an array?

Of course, the replacement will be completed when the query result is traversed, so it will be better.
The idea has been given to you, so you have to worry about it.