How to UPDATE XML using Modify [duplicate] - sql

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This question already has answers here:
TSQL 2005, XML DML - Update Two Values at once?
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Updating multiple XML nodes using T-SQL [duplicate]
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Closed 8 years ago.
I'm using SQL Server and have Table with XML column. My procedure for insert has input parameter XML document. Is there any way how could I update already existing XML in my table?
This is my OLD XML in my table:
<weather Location="Paris, France">
<forecast>
<description>Sky is clear</description>
<Date>2013-09-19</Date>
<MinTemp>13</MinTemp>
<MaxTemp>20</MaxTemp>
<Humidity>78</Humidity>
<Pressure>1024</Pressure>
<Windspeed>3</WindSpeed>
</forecast>
<forecast>
<description>Sky is clear</description>
<Date>2013-09-20</Date>
<MinTemp>14</MinTemp>
<MaxTemp>21</MaxTemp>
<Humidity>75</Humidity>
<Pressure>1020</Pressure>
<Windspeed>1</WindSpeed>
</forecast> .... 10 times this forecast
</weather>
This is my new one:
<weather Location="Paris, France">
<forecast>
<description>Sky is clear</description>
<Date>2013-09-19</Date>
<MinTemp>14</MinTemp>
<MaxTemp>21</MaxTemp>
<Humidity>70</Humidity>
<Pressure>1000</Pressure>
<Windspeed>5</WindSpeed>
</forecast>
<forecast>
<description>Sky is clear</description>
<Date>2013-09-20</Date>
<MinTemp>17</MinTemp>
<MaxTemp>24</MaxTemp>
<Humidity>68</Humidity>
<Pressure>1024</Pressure>
<Windspeed>3</WindSpeed>
</forecast> .... 10 times this forecast
</weather>
What I want now is to update my old XML with values I read from new one. I know I have to somehow go trough my OLD XML, I think I could do that with ...while(exist) and modify, but how to read value I need from my new XML, how to read let's say data for September 19th, and update September 19th in old XML, then read data for September 20th, then update September 20th in old XML etc etc...?
Thanks for help...

Answer 1

You may try likethis:-
update tbl1
set myXml.modify('replace value of (/weather/forecast/..)[1]
with concat(string(sql:column("columnname")), "value")')
where myXml.exist('/weather/forecast/..') = 1 //some condition