Fetch a value from a column which contains XML - sql

How to fetch a value from a column which contains XML in SQL Server?
below is my sample XML column value and the id's can be swap anytime(101,100) or (201,100,101,321).
<Questions>
<item id="101">Yes</item>
<item id="100">No</item>
</Questions>
I want to fetch a value based on Id. Like fetching Yes from id=101.
Sample code much appreciated.
I tried with below sample, but Unable to retrieve value "Yes"
select Y.value('#item[1]','varchar[3]') as valT from tbl_storeXML s cross apply s.Questions.nodes('Questions/item') as X(Y) where e.empId=256 and Y.value('#id','int')=101
Please help on this.
Ps. It's not a home work, I am learning handling xml in sql server.

Use of the value is not done correct, you do:
Y.value('#id','int')
This should be: Y.value('(#id)[1]','int')
round braces around #id, see: docs: value() Method
and Y.value('item[1]','varchar[3]').
This should be: Y.value('(#item)[1]','varchar(3)').
The # is removed because item is not an attribute
varchar should have round braces, not square braces.
Your try, after changes will become:
select
Y.value('(item)[1]','varchar(3)') as valT
from tbl_storeXML s
cross apply s.Questions.nodes('Questions/item') as X(Y)
where e.empId=256 and Y.value('(#id)','int')=101
This is not tested, because I do not have those tables. (I do think Y.value('(item)[1]','varchar(3)') might need to be written as Y.value('(.)[1]','varchar(3)') )
But the same approach can be seen in this DBFIDDLE
DECLARE #xml XML = '<Questions>
<item id="101">Yes</item>
<item id="100">No</item>
</Questions>';
select
X.y.value('(#id)[1]','VARCHAR(20)') id,
X.y.value('(.)[1]','VARCHAR(20)') value
from #xml.nodes('Questions/item') as X(y);
output:
id
value
101
Yes
100
No

Related

Count non-empty nodes in XML in SQL Server

I need to count all b nodes which are not empty (so result should be 2).
<a>
<b>1</b>
<b/>
<b>g</b>
</a>
I'm using code below but this returns count off all nodes (empty included).
select top 1 rc.XmlContent.value('count(//a/b)', 'int') from Table rc
If you use //a/b/text() rather than just //a/b, then you get a count of 2
DECLARE #x XML= '<a><b>1</b><b/><b>g</b></a>';
SELECT #x.value('count(//a/b/text())', 'int');
Sorry, this is not the answer! I misread this completely and thought your are looking for the empty nodes. There is an appropriate answer given by GarethD already (same idea, just the other way round).
I don't delete it, because it might help others...
The empty element <b/> (same as <b></b>) is existing but has no text().
DECLARE #xml XML =
N'<a>
<b>1</b>
<b/>
<b></b>
<b>g</b>
</a>';
select #xml.value('count(/a/b[empty(text())])', 'int')
This returns 2, because there is <b/> and <b></b>.
Just for completeness, you might negate the predicate, which is your needed result actually:
select #xml.value('count(/a/b[not(empty(text()))])', 'int')
Use this XPath expression
count(/a/b[normalize-space(text())=''])
Incorporated in your code it would look like this:
select top 1 rc.XmlContent.value('count(/a/b[normalize-space(text())=""])', 'int') from Table rc

Extract Value from XML having same tag name in SQL Server

I have XML variable defined below and its value.
I want to fetch the text defined between tag <TextNodeChild> in single query.
Kindly help.
Declare #XMLVariable =
'<?xml version="1.0"?>
<root>
<TextNodeParent>
<TextNodeChild>12345</TextNodeChild>
<TextNodeChild>67890</TextNodeChild>
<TextNodeChild>12389</TextNodeChild>
</TextNodeParent>
</root>'
I need output like this:
12345
67890
12389
You could use the XQuery (i.e. XML query) .nodes() method
SELECT
TextNodeParent = n.value('.[1]', 'NVARCHAR(max)')
FROM
#XMLVariable.nodes('root/TextNodeParent/*') as p(n)
EDIT : If you want to just the select the TextNodeChild node data then little change in xml path as follow
#XMLVariable.nodes('root/TextNodeParent/TextNodeChild') as p(n)
Result
TextNodeParent
12345
67890
12389
#YogeshSharma's solution works - here - because you have nothing but <TextNodeChild> elements under your <TextNodeParent> node.
However, if you had various node, and you wanted to extract only the <TextNodeChild> ones and get their values (and ignore all others), you'd have to use something like this instead:
SELECT
TextNodeParent = XC.value('.', 'INT')
FROM
#XMLVariable.nodes('root/TextNodeParent/TextNodeChild') as XT(XC)

SQL query to get most recent date from XML document

I am doing a SQL query against a column with an XML document located.
The XML document looks like the following.
<root>
<date>2016-10-12</date>
<date>2016-12-01</date>
<date>2016-11-13</date>
</root>
As you can see the dates are out of order.
I am looking for a SQL query that will get the most recent date from the XML document (in this case: 2016-12-01).
One way is to read all data and find the maximum externally (external ORDER BY with TOP 1, like in Prdp's answer, or MAX(), eventually with GROUP BY).
Another way is a FLWOR-XQuery:
DECLARE #xml XML=
'<root>
<date>2016-10-12</date>
<date>2016-12-01</date>
<date>2016-11-13</date>
</root>';
SELECT #xml.value('max(for $d in /root/date return xs:date($d))','date')
This means:
Take each value in /root/date, return it as date and find the highest!
Both approaches will need to read the whole list, but it should be a bit faster only to look for the maximum value, rather than return a full list and do some external sorting, picking again...
Try this
DECLARE #xml XML
SET #xml = '<root>
<date>2016-10-12</date>
<date>2016-12-01</date>
<date>2016-11-13</date>
</root>'
SELECT Top 1 x.col.value('.', 'date') AS dates
FROM #xml.nodes('/root/date') x(col)
ORDER BY dates DESC

extracting all tags(duplicates also) with specified name from xmltype column in sql

i want to extract a tag from an xml and insert into another table.
this XML is having different name spaces hence i use local-name() to fetch the tag which i want.
but some times there are multiple tags with same name. hence its failing with EXACTFETCH RETURNS MULTIPLE NODES. when multiple tags are existed i want to consider both instead of ignoring the second occurence.
source_table(id, payload):
id : 10
payload :
<root>
<name>john</name>
<status>
<statuscode>1</statuscode>
<statusmessage>one</statusmessage>
<statuscode>2</statuscode>
<statusmessage>two</statusmessage>
</status>
</root>
i want to extract stauscode and message and insert into another table
destination_table(id,name,statuscode,message)
output
10,john,1,one
10,john,2,two
below is the query i used
select id,
extract(payload, '//*[local-name()="name"]'),
extract(payload, '//*[local-name()="statuscode"]'),
extract(payload, '//*[local-name()="statusmessage"]')
from source_table;
i can get first occurence or second occurence by specifying [1] or [2] but i need both the stauscodes to be displayed like below
10,john,1,one
10,john,2,two
any help here
Hope this is what you need: Just past this into an empty query window and execute. Adapt it for your needs:
This solution assumes, that the status codes are sorted (as in your example 1,2,...). If this could occur in random order, just ask again...
Short explanation: The CTE "NameAndCode" brings up the name and the statuscodes. The ROW_NUMBER-function give us the node's index. This index I use to fetch the right message.
One more hint: If you can change the XML's format, it would be better to make the message an attribut of statuscode or to have it as subnode...
DECLARE #xmlColumn XML='<root>
<name>john</name>
<status>
<statuscode>1</statuscode>
<statusmessage>one</statusmessage>
<statuscode>2</statuscode>
<statusmessage>two</statusmessage>
</status>
</root>';
WITH NameAndCode AS
(
SELECT #xmlColumn.value('(/root/name)[1]','varchar(max)') AS Name
,x.y.value('.','int') AS Statuscode
,x.y.query('..') XMLNode
,ROW_NUMBER() OVER(ORDER BY x.y.value('.','int')) AS StatusIndex
FROM #xmlColumn.nodes('/root/status/statuscode') AS x(y)
)
SELECT *
,XMLNode.value('(/status[1]/statusmessage[sql:column("StatusIndex")])[1]','varchar(max)')
FROM NameAndCode

Modify XML values identified through cross apply

I've got a data issue with some values stored in an XML column in a database. I've reproduced the problem as the following example:
Setup Script:
create table XMLTest
(
[XML] xml
)
--A row with two duff entries
insert XMLTest values ('
<root>
<item>
<flag>false</flag>
<frac>0.5</frac>
</item>
<item>
<flag>false</flag>
<frac>0</frac>
</item>
<item>
<flag>false</flag>
<frac>0.5</frac>
</item>
<item>
<flag>true</flag>
<frac>0.5</frac>
</item>
</root>
')
In the XML portion the incorrect entries are those with <flag>false</flag> and <frac>0.5</frac> as the value of flag should be true for non-zero frac values.
The following SQL identifies the XML item nodes that require update:
select
i.query('.')
from
XMLTest
cross apply xml.nodes('root/item[flag="false" and frac > 0]') x(i)
I want to do an update to correct these nodes, but I don't see how to modify the item elements identified by a cross apply. I saw the update as looking something like this:
update t
set
x.i.modify('replace value of (flag/text())[1] with "true"')
from
XMLTest t
cross apply xml.nodes('root/item[flag="false" and frac > 0]') x(i)
However this isn't working: I get the error "Incorrect syntax near 'modify'".
Can this be done through this method?
I know an alternative would be to do a string replace on the xml column, but I don't like that as being a bit unsubtle (and I'm not confident it wouldn't break things in my real-word problem)
It is not possible to update the one XML instance in more than one place at a time so you have to do the updates in a loop until you are done.
From http://msdn.microsoft.com/en-us/library/ms190675.aspx "Expression1: Identifies a node whose value is to be updated. It must identify only a single node."
-- While there are rows that needs to be updated
while exists(select *
from XMLTest
where [XML].exist('root/item[flag="false" and frac > 0]') = 1)
begin
-- Update the first occurence in each XML instance
update XMLTest set
[XML].modify('replace value of (root/item[flag="false" and frac > 0]/flag/text())[1] with "true"')
where xml.exist('root/item[flag="false" and frac > 0]') = 1
end