How to extract value of all the child nodes of a specific node (provided through input parameter) from XMLType Column in Oracle - sql

Question

One of our requirements is to get the value of all the child nodes of a given specific XML node.
I have got a solution for this using Microsoft SQL Server but I need the same in Oracle. Please see the below query.
Note: incase if there is more than one child node, the result should be the concatenation of all the individual child nodes'value.
select
REPLACE(Properties, 'utf-8', 'utf-16'),
CAST(REPLACE(Col1, 'utf-8', 'utf-16') as XML).value('(//*[local-name() = sql:variable("#var2")])[1]', 'varchar(200)')
from A
Following is a sample data/row from Col1:
<?xml version="1.0" encoding="utf-8"?><ConstantInputProperties xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><Value xsi:type="xsd:int">0</Value></ConstantInputProperties>
here A is the table and Col1 is one of the columns of table A.
I tried to convert below Solution but it gives me the XML instead of values.
SELECT col1,
EXTRACT(XMLTYPE(col1), '(/*[local-name()="ConstantInputProperties"][1])')
FROM A
Example:
<?xml version="1.0" encoding="utf-8"?><ConstantInputProperties xmlns:xsd="w3.org/2001/XMLSchema" xmlns:xsi="w3.org/2001/XMLSchema-instance"><Value xsi:type="ArrayOfInt"><int>0</int><int>1</int></Value></ConstantInputProperties>
Expected Output 01
<?xml version="1.0" encoding="utf-8"?><ConstantInputProperties xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><Value xsi:type="ArrayOfBoolean"><boolean>true</boolean><boolean>true</boolean><boolean>true</boolean><boolean>true</boolean><boolean>true</boolean></Value></ConstantInputProperties>
Expected Output truetruetruetruetrue
<?xml version="1.0" encoding="utf-8"?><ConstantInputProperties xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><Value xsi:type="ArrayOfDecimal"><decimal>1.0000000000</decimal></Value></ConstantInputProperties>
Expected Output 1.0000000000

Answer 1

You could manipulate the XML inside an XPath with FLWOR syntax, but you could also use XMLTable to extract all the values; or rather, two XMLTables, one for a singleton element type and a second optional one for array expansion; get all the values as strings; and aggregate the results together:
select a.id,
listagg(coalesce(x1.value, x2.value), ' ')
within group (order by coalesce(x1.n, x2.n)) as result
from a
cross apply xmltable (
'(/*[local-name()=$var1][1])'
passing xmltype(col1), 'ConstantInputProperties' as "var1"
columns
n for ordinality,
value varchar2(30) path 'Value[#xsi:type="xsd:int"]',
array xmltype path 'Value[fn:starts-with(#xsi:type, "ArrayOf")]'
) x1
outer apply xmltable (
'Value/*'
passing array
columns
n for ordinality,
value varchar2(30) path '.'
) x2
group by a.id;
ID | RESULT
-: | :-----------------------
1 | 0
2 | 0 1
3 | true true true true true
4 | 1.0000000000
db<>fiddle
The n for ordinality just gives a numeric value that lets you keep the original sub-element order when aggregating (so you get 0 1 and not 1 0), If you don't want a spaces added to to the aggregated value then just change the second listagg argument from ' ' to null, though then you can't sell the difference between a singleton 10 and a pair of values with 1 and 0, so that doesn't seem very useful - not that an aggregated value seems that useful anyway really.
You could split into multiple sub-XMLTables, but that's probably not going to gain you anything here; db<>fiddle for info though.
can you suggest how to pass the ConstantInputProperties value as an argument and use it as a variable in function input in this case EXTRACT(XMLTYPE(col1), '(/[local-name()="ConstantInputProperties"]//text())')
The extract() function is deprecated. Use XMLQuery instead; for example:
select xmlquery(
'(/*[local-name()=$var1][1])/Value/text()'
passing xmltype(col1), 'ConstantInputProperties' as "var1"
returning content)
from a

Answer 2

Few examples:
with a as (
select q'[<?xml version="1.0" encoding="utf-8"?><ConstantInputProperties xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><Value xsi:type="xsd:int">0</Value></ConstantInputProperties>
]' col1 from dual
)
select
x.*
from
a,
xmltable(
'//*[local-name()="ConstantInputProperties"][1]'
passing xmltype(a.col1)
columns
res xmltype path '.'
) x;
--Result:
RES
------------------------------------------------------------------------------
<ConstantInputProperties xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><Value xsi:type="xsd:int">0</Value></ConstantInputProperties>
with a as (
select q'[<?xml version="1.0" encoding="utf-8"?><ConstantInputProperties xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><Value xsi:type="xsd:int">0</Value></ConstantInputProperties>
]' col1 from dual
)
select
x.*
from
a,
xmltable(
'//*[local-name()="ConstantInputProperties"]/*/text()'
passing xmltype(a.col1)
columns
res xmltype path '.'
) x;
--Result:
RES
--------------------------------------------------------------
<Value xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="xsd:int">0</Value>