remove duplicate entry in xml in mysql - mysql

Question

I have duplicate entry in my xml column in my sql table see material8 key.I remove one entry.I am trying below query its removing both.Is there any way i can remove only one entry.
Update mytable set xml = replace (xml, "<Book key=\"material8\" active=\"true\" displayOrder=\"5\" />", "") where id = 9 and type_key="mykey1";
<?xml version="1.0" encoding="UTF-8"?>
<Type key="test1" publicKey="test2" >
<UIProperties>
<label locale="en_US">My book</label>
</UIProperties>
<Books>
<Book key="material1" active="true" displayOrder="0" >
<UIProperties>
<label locale="en_US">My Books</label>
</UIProperties>
</Book>
<Book key="material2" />
<Book key="material3" active="true" displayOrder="3" >
<Pages>
<Page key="material4" active="true" displayOrder="0" />
<Page key="material5" active="true" displayOrder="1" />
</Pages>
</Book>
<Book key="material6" active="true" displayOrder="4" />
<Book key="material7" active="true" displayOrder="2" />
<Book key="material8" active="true" displayOrder="5" />
<Book key="material8" active="true" displayOrder="5" />
</Books>
<Attributes>
<Attribute key="desc" />
<Attribute key="date1" />
<Attribute key="date2" />
</Attributes>
</Type>

Answer 1

A simple solution is to replace 2 books to 1, instead of 1 to none:
UPDATE mytable
SET xml = REPLACE(xml, "<Book key=\"material8\" active=\"true\" displayOrder=\"5\" /><Book key=\"material8\" active=\"true\" displayOrder=\"5\" />", "<Book key=\"material8\" active=\"true\" displayOrder=\"5\" />")
WHERE id = 9
AND type_key="mykey1";