CODEWITHSUNDEEP
sqlsql-serverxmlsql-server-2005
Jon
Jon

Reputation: 40062

Use a LIKE statement on SQL Server XML Datatype

If you have a varchar field you can easily do SELECT * FROM TABLE WHERE ColumnA LIKE '%Test%' to see if that column contains a certain string.

How do you do that for XML Type?

I have the following which returns only rows that have a 'Text' node but I need to search within that node

select * from WebPageContent where data.exist('/PageContent/Text') = 1

Upvotes: 113

Views: 183904

Answers (5)

Charlieface
Charlieface

Reputation: 72480

The correct way to do this is to use the contains() XQuery predicate

SELECT *
FROM WebPageContent wpc
WHERE wpc.data.exist('/PageContent/Text/text()[contains(., "Test")]') = 1;

Upvotes: 0

Squazz
Squazz

Reputation: 4171

Yet another option is to cast the XML as nvarchar, and then search for the given string as if the XML vas a nvarchar field.

SELECT * 
FROM Table
WHERE CAST(Column as nvarchar(max)) LIKE '%TEST%'

I love this solution as it is clean, easy to remember, hard to mess up, and can be used as a part of a where clause.

This might not be the best performing solution, so think twice before deploying it to production. It is however very useful for a quick debug session, which is where I mostly use it.

EDIT: As Cliff mentions it, you could use:

...nvarchar if there's characters that don't convert to varchar

Upvotes: 142

Jon
Jon

Reputation: 40062

This is what I am going to use based on marc_s answer:

SELECT 
SUBSTRING(DATA.value('(/PAGECONTENT/TEXT)[1]', 'VARCHAR(100)'),PATINDEX('%NORTH%',DATA.value('(/PAGECONTENT/TEXT)[1]', 'VARCHAR(100)')) - 20,999)

FROM WEBPAGECONTENT 
WHERE COALESCE(PATINDEX('%NORTH%',DATA.value('(/PAGECONTENT/TEXT)[1]', 'VARCHAR(100)')),0) > 0

Return a substring on the search where the search criteria exists

Upvotes: 0

Carl Onager
Carl Onager

Reputation: 4122

Another option is to search the XML as a string by converting it to a string and then using LIKE. However as a computed column can't be part of a WHERE clause you need to wrap it in another SELECT like this:

SELECT * FROM
    (SELECT *, CONVERT(varchar(MAX), [COLUMNA]) as [XMLDataString] FROM TABLE) x
WHERE [XMLDataString] like '%Test%'

Upvotes: 13

marc_s
marc_s

Reputation: 755451

You should be able to do this quite easily:

SELECT * 
FROM WebPageContent 
WHERE data.value('(/PageContent/Text)[1]', 'varchar(100)') LIKE 'XYZ%'

The .value method gives you the actual value, and you can define that to be returned as a VARCHAR(), which you can then check with a LIKE statement.

Mind you, this isn't going to be awfully fast. So if you have certain fields in your XML that you need to inspect a lot, you could:

  • create a stored function which gets the XML and returns the value you're looking for as a VARCHAR()
  • define a new computed field on your table which calls this function, and make it a PERSISTED column

With this, you'd basically "extract" a certain portion of the XML into a computed field, make it persisted, and then you can search very efficiently on it (heck: you can even INDEX that field!).

Marc

Upvotes: 76

Related Questions