The placement of the where clause in a query affects processing. For example, this query selects all the books whose author’s first name is Mary:
select com.sybase.xml.xql.Xql.query
("/bookstore/book[author/first-name ='Mary']", xmlcol)
from XMLDAT
where
com.sybase.xml.xql.Xql.query
("/bookstore/book
[author/first-name= ‘Mary’]", xmlcol)!=
convert(com.sybase.xml.xql.Xql, null)>>EmptyResult
<xql_result ><book style="textbook">
<title>History of Trenton</title>
<author>
<first-name>Mary</first-name>
<last-name>Bob</last-name>
<publication>
Selected Short Stories of
<first-name>Mary</first-name>
<last-name>Bob</last-name>
</publication>
</author>
<price>55</price>
</book></xql_result>
