I have the following tables
A (ID, relatedID, typeId )
B (ID, leftID, leftTypeId)
I want to join the two tables like this
select * from A
inner join B on A.TypeId=B.LeftTypeId and {condition}
where condition should verify id the leftID would match a value from relatedID , where relatedId is a xml column. Eg. relatedID= <Id>1</Id>
Is there a optimal way to do this?
UPDATE relatedID
can contain several Ids. Eg Eg. relatedID=<Id>1</Id><Id>2</Id>
You may use
... and A.relatedID.value('(/Id[1]/text())[1]', 'int') = B.leftID
or
... and A.relatedID.exist('(/Id[1]/text())[1] = sql:column("B.leftID")') = 1
Though exist
is recommended over value
for predicates, depending on whether the XML
column is xml-indexed or not and what type of indexes it has, one of the two above may perform better.
upd. for the case when relatedID can contain set of Ids you may try
select ...
from A
cross apply A.relatedID.nodes('/Id') r(id)
inner join B on A.TypeId=B.LeftTypeId
and r.id.value('text()[1]', 'int') = B.leftID
or
select ...
from A
cross apply A.relatedID.nodes('/Id') r(id)
inner join B on A.TypeId=B.LeftTypeId
and r.id.exist('text()[1]=sql:column("B.leftID")') = 1
or even
select ...
from A
inner join B on A.TypeId=B.LeftTypeId
and A.relatedID.exist('/Id[text()[1]=sql:column("B.leftID")]') = 1
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