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How to Use Merge Statement Using XML Data

We now that merge statement in SQL SERVER. With Merge statement we can merge the data from Source table into Target table.

In the Last article we have already seen about Merge Statement.  

These articles we will work around merge statement over xml data type. We know that xml data type SQL SERVER. XML Data type is used to storing xml data used Bulk Insert Data into SQL Tables.

Example:

--Create Student Table
if object_id('Student') is null
create table Student(id int identity(1,1) ,Name varchar(20), Marks int)





Declare Xml Data Type and Assign Some Xml Data.
Declare @Data xml

set @Data=
'<Root>
<Student>
<Name>Rakesh</Name>
<Marks>80</Marks>
</Student>
<Student>
<Name>Mahesh</Name>
<Marks>90</Marks>
</Student>
<Student>
<Name>Gowtham</Name>
<Marks>60</Marks>
</Student>
</Root>'
select @Data as StudentData

 select * from Student

--no record in Student Table

Merge Statement usign Xml Data.

Merge into Student as Trg
Using (select d.x.value('Name[1]','varchar(20)') as Name ,
d.x.value('Marks[1]','int') as Marks from
@data.nodes('/Root/Student')as  d(x)) as Src
on Trg.Name=Src.Name
When Matched Then update set
Trg.Marks=Src.Marks
when not matched by target then
insert (Name,Marks) values(Src.Name,Src.Marks);


select * from Student

















Here All rows gets inserted because of no matched records existed in Student table with Name Key 

This time I changed the Xml Data Marks Column With Same Data this time need to update Student table Data.

Declare @Data xml

set @Data=
'<Root>
<Student>
<Name>Rakesh</Name>
<Marks>60</Marks>
</Student>
<Student>
<Name>Mahesh</Name>
<Marks>90</Marks>
</Student>
<Student>
<Name>Gowtham</Name>
<Marks>80</Marks>
</Student>
</Root>'

Merge into Student as Trg
Using (select d.x.value('Name[1]','varchar(20)') as Name
,d.x.value('Marks[1]','int') as Marks from
@data.nodes('/Root/Student')as  d(x)) as Src
on Trg.Name=Src.Name
When Matched Then update set
Trg.Marks=Src.Marks
when not matched by target then
insert (Name,Marks) values(Src.Name,Src.Marks);


select * from Student




  
Remove Some Data from Xml (“Here GoWtham “ Record)



Declare @Data xml

set @Data=
'<Root>
<Student>
<Name>Rakesh</Name>
<Marks>60</Marks>
</Student>
<Student>
<Name>Mahesh</Name>
<Marks>90</Marks>
</Student>
</Root>'

Merge into Student as Trg
Using (select d.x.value('Name[1]','varchar(20)') as Name
,d.x.value('Marks[1]','int') as Marks from
@data.nodes('/Root/Student')as  d(x)) as Src
on Trg.Name=Src.Name
When Matched Then update set
Trg.Marks=Src.Marks
when not matched by target then
insert (Name,Marks) values(Src.Name,Src.Marks)
when not matched by source then Delete;


select * from Student





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