Use PHP language to import MySQL data into an XML file

To import MySQL data into an XML file in PHP language
I want to use PHP to import the table in MySQL: Floor data into a specified test.xml file. On the Internet to find some methods ineffective, I hope to have done a friend to reward the source code.
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It's probably meant to be, but I just don't know how to output the MySQL database in this XML file.

So you always have to query, save the results of the query to the array will always it?

Of course, when you traverse the results of the query to complete the replacement, it's even better.
You have to think about it.

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